// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
 * This file contains the login functions used by the iSCSI Target driver.
 *
 * (c) Copyright 2007-2013 Datera, Inc.
 *
 * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 ******************************************************************************/

#include <linux/module.h>
#include <linux/string.h>
#include <linux/kthread.h>
#include <linux/sched/signal.h>
#include <linux/idr.h>
#include <linux/tcp.h>        /* TCP_NODELAY */
#include <net/ip.h>
#include <net/ipv6.h>         /* ipv6_addr_v4mapped() */
#include <scsi/iscsi_proto.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>

#include <target/iscsi/iscsi_target_core.h>
#include <target/iscsi/iscsi_target_stat.h>
#include "iscsi_target_device.h"
#include "iscsi_target_nego.h"
#include "iscsi_target_erl0.h"
#include "iscsi_target_erl2.h"
#include "iscsi_target_login.h"
#include "iscsi_target_tpg.h"
#include "iscsi_target_util.h"
#include "iscsi_target.h"
#include "iscsi_target_parameters.h"

#include <target/iscsi/iscsi_transport.h>

static struct iscsi_login *iscsi_login_init_conn(struct iscsit_conn *conn)
{
        struct iscsi_login *login;

        login = kzalloc_obj(struct iscsi_login);
        if (!login) {
                pr_err("Unable to allocate memory for struct iscsi_login.\n");
                return NULL;
        }
        conn->login = login;
        login->conn = conn;
        login->first_request = 1;

        login->req_buf = kzalloc(MAX_KEY_VALUE_PAIRS, GFP_KERNEL);
        if (!login->req_buf) {
                pr_err("Unable to allocate memory for response buffer.\n");
                goto out_login;
        }

        login->rsp_buf = kzalloc(MAX_KEY_VALUE_PAIRS, GFP_KERNEL);
        if (!login->rsp_buf) {
                pr_err("Unable to allocate memory for request buffer.\n");
                goto out_req_buf;
        }

        conn->conn_login = login;

        return login;

out_req_buf:
        kfree(login->req_buf);
out_login:
        kfree(login);
        return NULL;
}

static int iscsi_login_check_initiator_version(
        struct iscsit_conn *conn,
        u8 version_max,
        u8 version_min)
{
        if ((version_max != 0x00) || (version_min != 0x00)) {
                pr_err("Unsupported iSCSI IETF Pre-RFC Revision,"
                        " version Min/Max 0x%02x/0x%02x, rejecting login.\n",
                        version_min, version_max);
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_INITIATOR_ERR,
                                ISCSI_LOGIN_STATUS_NO_VERSION);
                return -1;
        }

        return 0;
}

int iscsi_check_for_session_reinstatement(struct iscsit_conn *conn)
{
        int sessiontype;
        struct iscsi_param *initiatorname_param = NULL, *sessiontype_param = NULL;
        struct iscsi_portal_group *tpg = conn->tpg;
        struct iscsit_session *sess = NULL, *sess_p = NULL;
        struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
        struct se_session *se_sess, *se_sess_tmp;

        initiatorname_param = iscsi_find_param_from_key(
                        INITIATORNAME, conn->param_list);
        sessiontype_param = iscsi_find_param_from_key(
                        SESSIONTYPE, conn->param_list);
        if (!initiatorname_param || !sessiontype_param) {
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_INITIATOR_ERR,
                        ISCSI_LOGIN_STATUS_MISSING_FIELDS);
                return -1;
        }

        sessiontype = (strncmp(sessiontype_param->value, NORMAL, 6)) ? 1 : 0;

        spin_lock_bh(&se_tpg->session_lock);
        list_for_each_entry_safe(se_sess, se_sess_tmp, &se_tpg->tpg_sess_list,
                        sess_list) {

                sess_p = se_sess->fabric_sess_ptr;
                spin_lock(&sess_p->conn_lock);
                if (atomic_read(&sess_p->session_fall_back_to_erl0) ||
                    atomic_read(&sess_p->session_logout) ||
                    atomic_read(&sess_p->session_close) ||
                    (sess_p->time2retain_timer_flags & ISCSI_TF_EXPIRED)) {
                        spin_unlock(&sess_p->conn_lock);
                        continue;
                }
                if (!memcmp(sess_p->isid, conn->sess->isid, 6) &&
                   (!strcmp(sess_p->sess_ops->InitiatorName,
                            initiatorname_param->value) &&
                   (sess_p->sess_ops->SessionType == sessiontype))) {
                        atomic_set(&sess_p->session_reinstatement, 1);
                        atomic_set(&sess_p->session_fall_back_to_erl0, 1);
                        atomic_set(&sess_p->session_close, 1);
                        spin_unlock(&sess_p->conn_lock);
                        iscsit_inc_session_usage_count(sess_p);
                        iscsit_stop_time2retain_timer(sess_p);
                        sess = sess_p;
                        break;
                }
                spin_unlock(&sess_p->conn_lock);
        }
        spin_unlock_bh(&se_tpg->session_lock);
        /*
         * If the Time2Retain handler has expired, the session is already gone.
         */
        if (!sess)
                return 0;

        pr_debug("%s iSCSI Session SID %u is still active for %s,"
                " performing session reinstatement.\n", (sessiontype) ?
                "Discovery" : "Normal", sess->sid,
                sess->sess_ops->InitiatorName);

        spin_lock_bh(&sess->conn_lock);
        if (sess->session_state == TARG_SESS_STATE_FAILED) {
                spin_unlock_bh(&sess->conn_lock);
                iscsit_dec_session_usage_count(sess);
                return 0;
        }
        spin_unlock_bh(&sess->conn_lock);

        iscsit_stop_session(sess, 1, 1);
        iscsit_dec_session_usage_count(sess);

        return 0;
}

static int iscsi_login_set_conn_values(
        struct iscsit_session *sess,
        struct iscsit_conn *conn,
        __be16 cid)
{
        int ret;
        conn->sess              = sess;
        conn->cid               = be16_to_cpu(cid);
        /*
         * Generate a random Status sequence number (statsn) for the new
         * iSCSI connection.
         */
        ret = get_random_bytes_wait(&conn->stat_sn, sizeof(u32));
        if (unlikely(ret))
                return ret;

        mutex_lock(&auth_id_lock);
        conn->auth_id           = iscsit_global->auth_id++;
        mutex_unlock(&auth_id_lock);
        return 0;
}

__printf(2, 3) int iscsi_change_param_sprintf(
        struct iscsit_conn *conn,
        const char *fmt, ...)
{
        va_list args;
        unsigned char buf[64];

        memset(buf, 0, sizeof buf);

        va_start(args, fmt);
        vsnprintf(buf, sizeof buf, fmt, args);
        va_end(args);

        if (iscsi_change_param_value(buf, conn->param_list, 0) < 0) {
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                return -1;
        }

        return 0;
}
EXPORT_SYMBOL(iscsi_change_param_sprintf);

/*
 *      This is the leading connection of a new session,
 *      or session reinstatement.
 */
static int iscsi_login_zero_tsih_s1(
        struct iscsit_conn *conn,
        unsigned char *buf)
{
        struct iscsit_session *sess = NULL;
        struct iscsi_login_req *pdu = (struct iscsi_login_req *)buf;
        int ret;

        sess = kzalloc_obj(struct iscsit_session);
        if (!sess) {
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                pr_err("Could not allocate memory for session\n");
                return -ENOMEM;
        }

        if (iscsi_login_set_conn_values(sess, conn, pdu->cid))
                goto free_sess;

        sess->init_task_tag     = pdu->itt;
        memcpy(&sess->isid, pdu->isid, 6);
        sess->exp_cmd_sn        = be32_to_cpu(pdu->cmdsn);
        INIT_LIST_HEAD(&sess->sess_conn_list);
        INIT_LIST_HEAD(&sess->sess_ooo_cmdsn_list);
        INIT_LIST_HEAD(&sess->cr_active_list);
        INIT_LIST_HEAD(&sess->cr_inactive_list);
        init_completion(&sess->async_msg_comp);
        init_completion(&sess->reinstatement_comp);
        init_completion(&sess->session_wait_comp);
        init_completion(&sess->session_waiting_on_uc_comp);
        mutex_init(&sess->cmdsn_mutex);
        spin_lock_init(&sess->conn_lock);
        spin_lock_init(&sess->cr_a_lock);
        spin_lock_init(&sess->cr_i_lock);
        spin_lock_init(&sess->session_usage_lock);
        spin_lock_init(&sess->ttt_lock);

        timer_setup(&sess->time2retain_timer,
                    iscsit_handle_time2retain_timeout, 0);

        ret = ida_alloc(&sess_ida, GFP_KERNEL);
        if (ret < 0) {
                pr_err("Session ID allocation failed %d\n", ret);
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                goto free_sess;
        }

        sess->session_index = ret;
        sess->creation_time = get_jiffies_64();
        /*
         * The FFP CmdSN window values will be allocated from the TPG's
         * Initiator Node's ACL once the login has been successfully completed.
         */
        atomic_set(&sess->max_cmd_sn, be32_to_cpu(pdu->cmdsn));

        sess->sess_ops = kzalloc_obj(struct iscsi_sess_ops);
        if (!sess->sess_ops) {
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                pr_err("Unable to allocate memory for"
                                " struct iscsi_sess_ops.\n");
                goto free_id;
        }

        sess->se_sess = transport_alloc_session(TARGET_PROT_NORMAL);
        if (IS_ERR(sess->se_sess)) {
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                goto free_ops;
        }

        return 0;

free_ops:
        kfree(sess->sess_ops);
free_id:
        ida_free(&sess_ida, sess->session_index);
free_sess:
        kfree(sess);
        conn->sess = NULL;
        return -ENOMEM;
}

static int iscsi_login_zero_tsih_s2(
        struct iscsit_conn *conn)
{
        struct iscsi_node_attrib *na;
        struct iscsit_session *sess = conn->sess;
        struct iscsi_param *param;
        bool iser = false;

        sess->tpg = conn->tpg;

        /*
         * Assign a new TPG Session Handle.  Note this is protected with
         * struct iscsi_portal_group->np_login_sem from iscsit_access_np().
         */
        sess->tsih = ++sess->tpg->ntsih;
        if (!sess->tsih)
                sess->tsih = ++sess->tpg->ntsih;

        /*
         * Create the default params from user defined values..
         */
        if (iscsi_copy_param_list(&conn->param_list,
                                conn->tpg->param_list, 1) < 0) {
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                return -1;
        }

        if (conn->conn_transport->transport_type == ISCSI_INFINIBAND)
                iser = true;

        iscsi_set_keys_to_negotiate(conn->param_list, iser);

        if (sess->sess_ops->SessionType)
                return iscsi_set_keys_irrelevant_for_discovery(
                                conn->param_list);

        na = iscsit_tpg_get_node_attrib(sess);

        /*
         * If ACL allows non-authorized access in TPG with CHAP,
         * then set None to AuthMethod.
         */
        param = iscsi_find_param_from_key(AUTHMETHOD, conn->param_list);
        if (param && !strstr(param->value, NONE)) {
                if (!iscsi_conn_auth_required(conn))
                        if (iscsi_change_param_sprintf(conn, "AuthMethod=%s",
                                                       NONE))
                                return -1;
        }

        /*
         * Need to send TargetPortalGroupTag back in first login response
         * on any iSCSI connection where the Initiator provides TargetName.
         * See 5.3.1.  Login Phase Start
         *
         * In our case, we have already located the struct iscsi_tiqn at this point.
         */
        if (iscsi_change_param_sprintf(conn, "TargetPortalGroupTag=%hu", sess->tpg->tpgt))
                return -1;

        /*
         * Workaround for Initiators that have broken connection recovery logic.
         *
         * "We would really like to get rid of this." Linux-iSCSI.org team
         */
        if (iscsi_change_param_sprintf(conn, "ErrorRecoveryLevel=%d", na->default_erl))
                return -1;

        /*
         * Set RDMAExtensions=Yes by default for iSER enabled network portals
         */
        if (iser) {
                struct iscsi_param *param;
                unsigned long mrdsl, off;
                int rc;

                if (iscsi_change_param_sprintf(conn, "RDMAExtensions=Yes"))
                        return -1;

                /*
                 * Make MaxRecvDataSegmentLength PAGE_SIZE aligned for
                 * Immediate Data + Unsolicited Data-OUT if necessary..
                 */
                param = iscsi_find_param_from_key("MaxRecvDataSegmentLength",
                                                  conn->param_list);
                if (!param) {
                        iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                        return -1;
                }
                rc = kstrtoul(param->value, 0, &mrdsl);
                if (rc < 0) {
                        iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                        return -1;
                }
                off = mrdsl % PAGE_SIZE;
                if (!off)
                        goto check_prot;

                if (mrdsl < PAGE_SIZE)
                        mrdsl = PAGE_SIZE;
                else
                        mrdsl -= off;

                pr_warn("Aligning ISER MaxRecvDataSegmentLength: %lu down"
                        " to PAGE_SIZE\n", mrdsl);

                if (iscsi_change_param_sprintf(conn, "MaxRecvDataSegmentLength=%lu\n", mrdsl))
                        return -1;
                /*
                 * ISER currently requires that ImmediateData + Unsolicited
                 * Data be disabled when protection / signature MRs are enabled.
                 */
check_prot:
                if (sess->se_sess->sup_prot_ops &
                   (TARGET_PROT_DOUT_STRIP | TARGET_PROT_DOUT_PASS |
                    TARGET_PROT_DOUT_INSERT)) {

                        if (iscsi_change_param_sprintf(conn, "ImmediateData=No"))
                                return -1;

                        if (iscsi_change_param_sprintf(conn, "InitialR2T=Yes"))
                                return -1;

                        pr_debug("Forcing ImmediateData=No + InitialR2T=Yes for"
                                 " T10-PI enabled ISER session\n");
                }
        }

        return 0;
}

static int iscsi_login_non_zero_tsih_s1(
        struct iscsit_conn *conn,
        unsigned char *buf)
{
        struct iscsi_login_req *pdu = (struct iscsi_login_req *)buf;

        return iscsi_login_set_conn_values(NULL, conn, pdu->cid);
}

/*
 *      Add a new connection to an existing session.
 */
static int iscsi_login_non_zero_tsih_s2(
        struct iscsit_conn *conn,
        unsigned char *buf)
{
        struct iscsi_portal_group *tpg = conn->tpg;
        struct iscsit_session *sess = NULL, *sess_p = NULL;
        struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;
        struct se_session *se_sess, *se_sess_tmp;
        struct iscsi_login_req *pdu = (struct iscsi_login_req *)buf;
        bool iser = false;

        spin_lock_bh(&se_tpg->session_lock);
        list_for_each_entry_safe(se_sess, se_sess_tmp, &se_tpg->tpg_sess_list,
                        sess_list) {

                sess_p = (struct iscsit_session *)se_sess->fabric_sess_ptr;
                if (atomic_read(&sess_p->session_fall_back_to_erl0) ||
                    atomic_read(&sess_p->session_logout) ||
                    atomic_read(&sess_p->session_close) ||
                   (sess_p->time2retain_timer_flags & ISCSI_TF_EXPIRED))
                        continue;
                if (!memcmp(sess_p->isid, pdu->isid, 6) &&
                     (sess_p->tsih == be16_to_cpu(pdu->tsih))) {
                        iscsit_inc_session_usage_count(sess_p);
                        iscsit_stop_time2retain_timer(sess_p);
                        sess = sess_p;
                        break;
                }
        }
        spin_unlock_bh(&se_tpg->session_lock);

        /*
         * If the Time2Retain handler has expired, the session is already gone.
         */
        if (!sess) {
                pr_err("Initiator attempting to add a connection to"
                        " a non-existent session, rejecting iSCSI Login.\n");
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_INITIATOR_ERR,
                                ISCSI_LOGIN_STATUS_NO_SESSION);
                return -1;
        }

        /*
         * Stop the Time2Retain timer if this is a failed session, we restart
         * the timer if the login is not successful.
         */
        spin_lock_bh(&sess->conn_lock);
        if (sess->session_state == TARG_SESS_STATE_FAILED)
                atomic_set(&sess->session_continuation, 1);
        spin_unlock_bh(&sess->conn_lock);

        if (iscsi_login_set_conn_values(sess, conn, pdu->cid) < 0 ||
            iscsi_copy_param_list(&conn->param_list,
                        conn->tpg->param_list, 0) < 0) {
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_NO_RESOURCES);
                return -1;
        }

        if (conn->conn_transport->transport_type == ISCSI_INFINIBAND)
                iser = true;

        iscsi_set_keys_to_negotiate(conn->param_list, iser);
        /*
         * Need to send TargetPortalGroupTag back in first login response
         * on any iSCSI connection where the Initiator provides TargetName.
         * See 5.3.1.  Login Phase Start
         *
         * In our case, we have already located the struct iscsi_tiqn at this point.
         */
        if (iscsi_change_param_sprintf(conn, "TargetPortalGroupTag=%hu", sess->tpg->tpgt))
                return -1;

        return 0;
}

int iscsi_login_post_auth_non_zero_tsih(
        struct iscsit_conn *conn,
        u16 cid,
        u32 exp_statsn)
{
        struct iscsit_conn *conn_ptr = NULL;
        struct iscsi_conn_recovery *cr = NULL;
        struct iscsit_session *sess = conn->sess;

        /*
         * By following item 5 in the login table,  if we have found
         * an existing ISID and a valid/existing TSIH and an existing
         * CID we do connection reinstatement.  Currently we dont not
         * support it so we send back an non-zero status class to the
         * initiator and release the new connection.
         */
        conn_ptr = iscsit_get_conn_from_cid_rcfr(sess, cid);
        if (conn_ptr) {
                pr_err("Connection exists with CID %hu for %s,"
                        " performing connection reinstatement.\n",
                        conn_ptr->cid, sess->sess_ops->InitiatorName);

                iscsit_connection_reinstatement_rcfr(conn_ptr);
                iscsit_dec_conn_usage_count(conn_ptr);
        }

        /*
         * Check for any connection recovery entries containing CID.
         * We use the original ExpStatSN sent in the first login request
         * to acknowledge commands for the failed connection.
         *
         * Also note that an explict logout may have already been sent,
         * but the response may not be sent due to additional connection
         * loss.
         */
        if (sess->sess_ops->ErrorRecoveryLevel == 2) {
                cr = iscsit_get_inactive_connection_recovery_entry(
                                sess, cid);
                if (cr) {
                        pr_debug("Performing implicit logout"
                                " for connection recovery on CID: %hu\n",
                                        conn->cid);
                        iscsit_discard_cr_cmds_by_expstatsn(cr, exp_statsn);
                }
        }

        /*
         * Else we follow item 4 from the login table in that we have
         * found an existing ISID and a valid/existing TSIH and a new
         * CID we go ahead and continue to add a new connection to the
         * session.
         */
        pr_debug("Adding CID %hu to existing session for %s.\n",
                        cid, sess->sess_ops->InitiatorName);

        if ((atomic_read(&sess->nconn) + 1) > sess->sess_ops->MaxConnections) {
                pr_err("Adding additional connection to this session"
                        " would exceed MaxConnections %d, login failed.\n",
                                sess->sess_ops->MaxConnections);
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_INITIATOR_ERR,
                                ISCSI_LOGIN_STATUS_ISID_ERROR);
                return -1;
        }

        return 0;
}

static void iscsi_post_login_start_timers(struct iscsit_conn *conn)
{
        struct iscsit_session *sess = conn->sess;
        /*
         * FIXME: Unsolicited NopIN support for ISER
         */
        if (conn->conn_transport->transport_type == ISCSI_INFINIBAND)
                return;

        if (!sess->sess_ops->SessionType)
                iscsit_start_nopin_timer(conn);
}

int iscsit_start_kthreads(struct iscsit_conn *conn)
{
        int ret = 0;

        spin_lock(&iscsit_global->ts_bitmap_lock);
        conn->bitmap_id = bitmap_find_free_region(iscsit_global->ts_bitmap,
                                        ISCSIT_BITMAP_BITS, get_order(1));
        spin_unlock(&iscsit_global->ts_bitmap_lock);

        if (conn->bitmap_id < 0) {
                pr_err("bitmap_find_free_region() failed for"
                       " iscsit_start_kthreads()\n");
                return -ENOMEM;
        }

        conn->tx_thread = kthread_run(iscsi_target_tx_thread, conn,
                                      "%s", ISCSI_TX_THREAD_NAME);
        if (IS_ERR(conn->tx_thread)) {
                pr_err("Unable to start iscsi_target_tx_thread\n");
                ret = PTR_ERR(conn->tx_thread);
                goto out_bitmap;
        }
        conn->tx_thread_active = true;

        conn->rx_thread = kthread_run(iscsi_target_rx_thread, conn,
                                      "%s", ISCSI_RX_THREAD_NAME);
        if (IS_ERR(conn->rx_thread)) {
                pr_err("Unable to start iscsi_target_rx_thread\n");
                ret = PTR_ERR(conn->rx_thread);
                goto out_tx;
        }
        conn->rx_thread_active = true;

        return 0;
out_tx:
        send_sig(SIGINT, conn->tx_thread, 1);
        kthread_stop(conn->tx_thread);
        conn->tx_thread_active = false;
out_bitmap:
        spin_lock(&iscsit_global->ts_bitmap_lock);
        bitmap_release_region(iscsit_global->ts_bitmap, conn->bitmap_id,
                              get_order(1));
        spin_unlock(&iscsit_global->ts_bitmap_lock);
        return ret;
}

void iscsi_post_login_handler(
        struct iscsi_np *np,
        struct iscsit_conn *conn,
        u8 zero_tsih)
{
        int stop_timer = 0;
        struct iscsit_session *sess = conn->sess;
        struct se_session *se_sess = sess->se_sess;
        struct iscsi_portal_group *tpg = sess->tpg;
        struct se_portal_group *se_tpg = &tpg->tpg_se_tpg;

        iscsit_inc_conn_usage_count(conn);

        iscsit_collect_login_stats(conn, ISCSI_STATUS_CLS_SUCCESS,
                        ISCSI_LOGIN_STATUS_ACCEPT);

        pr_debug("Moving to TARG_CONN_STATE_LOGGED_IN.\n");
        conn->conn_state = TARG_CONN_STATE_LOGGED_IN;

        iscsi_set_connection_parameters(conn->conn_ops, conn->param_list);
        /*
         * SCSI Initiator -> SCSI Target Port Mapping
         */
        if (!zero_tsih) {
                iscsi_set_session_parameters(sess->sess_ops,
                                conn->param_list, 0);
                iscsi_release_param_list(conn->param_list);
                conn->param_list = NULL;

                spin_lock_bh(&sess->conn_lock);
                atomic_set(&sess->session_continuation, 0);
                if (sess->session_state == TARG_SESS_STATE_FAILED) {
                        pr_debug("Moving to"
                                        " TARG_SESS_STATE_LOGGED_IN.\n");
                        sess->session_state = TARG_SESS_STATE_LOGGED_IN;
                        stop_timer = 1;
                }

                pr_debug("iSCSI Login successful on CID: %hu from %pISpc to"
                        " %pISpc,%hu\n", conn->cid, &conn->login_sockaddr,
                        &conn->local_sockaddr, tpg->tpgt);

                list_add_tail(&conn->conn_list, &sess->sess_conn_list);
                atomic_inc(&sess->nconn);
                pr_debug("Incremented iSCSI Connection count to %d"
                        " from node: %s\n", atomic_read(&sess->nconn),
                        sess->sess_ops->InitiatorName);
                spin_unlock_bh(&sess->conn_lock);

                iscsi_post_login_start_timers(conn);
                /*
                 * Determine CPU mask to ensure connection's RX and TX kthreads
                 * are scheduled on the same CPU.
                 */
                iscsit_thread_get_cpumask(conn);
                conn->conn_rx_reset_cpumask = 1;
                conn->conn_tx_reset_cpumask = 1;
                /*
                 * Wakeup the sleeping iscsi_target_rx_thread() now that
                 * iscsit_conn is in TARG_CONN_STATE_LOGGED_IN state.
                 */
                complete(&conn->rx_login_comp);
                iscsit_dec_conn_usage_count(conn);

                if (stop_timer) {
                        spin_lock_bh(&se_tpg->session_lock);
                        iscsit_stop_time2retain_timer(sess);
                        spin_unlock_bh(&se_tpg->session_lock);
                }
                iscsit_dec_session_usage_count(sess);
                return;
        }

        iscsi_set_session_parameters(sess->sess_ops, conn->param_list, 1);
        iscsi_release_param_list(conn->param_list);
        conn->param_list = NULL;

        iscsit_determine_maxcmdsn(sess);

        spin_lock_bh(&se_tpg->session_lock);
        __transport_register_session(&sess->tpg->tpg_se_tpg,
                        se_sess->se_node_acl, se_sess, sess);
        pr_debug("Moving to TARG_SESS_STATE_LOGGED_IN.\n");
        sess->session_state = TARG_SESS_STATE_LOGGED_IN;

        pr_debug("iSCSI Login successful on CID: %hu from %pISpc to %pISpc,%hu\n",
                conn->cid, &conn->login_sockaddr, &conn->local_sockaddr,
                tpg->tpgt);

        spin_lock_bh(&sess->conn_lock);
        list_add_tail(&conn->conn_list, &sess->sess_conn_list);
        atomic_inc(&sess->nconn);
        pr_debug("Incremented iSCSI Connection count to %d from node:"
                " %s\n", atomic_read(&sess->nconn),
                sess->sess_ops->InitiatorName);
        spin_unlock_bh(&sess->conn_lock);

        sess->sid = tpg->sid++;
        if (!sess->sid)
                sess->sid = tpg->sid++;
        pr_debug("Established iSCSI session from node: %s\n",
                        sess->sess_ops->InitiatorName);

        tpg->nsessions++;
        if (tpg->tpg_tiqn)
                tpg->tpg_tiqn->tiqn_nsessions++;

        pr_debug("Incremented number of active iSCSI sessions to %u on"
                " iSCSI Target Portal Group: %hu\n", tpg->nsessions, tpg->tpgt);
        spin_unlock_bh(&se_tpg->session_lock);

        iscsi_post_login_start_timers(conn);
        /*
         * Determine CPU mask to ensure connection's RX and TX kthreads
         * are scheduled on the same CPU.
         */
        iscsit_thread_get_cpumask(conn);
        conn->conn_rx_reset_cpumask = 1;
        conn->conn_tx_reset_cpumask = 1;
        /*
         * Wakeup the sleeping iscsi_target_rx_thread() now that
         * iscsit_conn is in TARG_CONN_STATE_LOGGED_IN state.
         */
        complete(&conn->rx_login_comp);
        iscsit_dec_conn_usage_count(conn);
}

int iscsit_setup_np(
        struct iscsi_np *np,
        struct sockaddr_storage *sockaddr)
{
        struct socket *sock = NULL;
        int backlog = ISCSIT_TCP_BACKLOG, ret, len;

        switch (np->np_network_transport) {
        case ISCSI_TCP:
                np->np_ip_proto = IPPROTO_TCP;
                np->np_sock_type = SOCK_STREAM;
                break;
        case ISCSI_SCTP_TCP:
                np->np_ip_proto = IPPROTO_SCTP;
                np->np_sock_type = SOCK_STREAM;
                break;
        case ISCSI_SCTP_UDP:
                np->np_ip_proto = IPPROTO_SCTP;
                np->np_sock_type = SOCK_SEQPACKET;
                break;
        default:
                pr_err("Unsupported network_transport: %d\n",
                                np->np_network_transport);
                return -EINVAL;
        }

        ret = sock_create(sockaddr->ss_family, np->np_sock_type,
                        np->np_ip_proto, &sock);
        if (ret < 0) {
                pr_err("sock_create() failed.\n");
                return ret;
        }
        np->np_socket = sock;
        /*
         * Setup the np->np_sockaddr from the passed sockaddr setup
         * in iscsi_target_configfs.c code..
         */
        memcpy(&np->np_sockaddr, sockaddr,
                        sizeof(struct sockaddr_storage));

        if (sockaddr->ss_family == AF_INET6)
                len = sizeof(struct sockaddr_in6);
        else
                len = sizeof(struct sockaddr_in);
        /*
         * Set SO_REUSEADDR, and disable Nagle Algorithm with TCP_NODELAY.
         */
        if (np->np_network_transport == ISCSI_TCP)
                tcp_sock_set_nodelay(sock->sk);
        sock_set_reuseaddr(sock->sk);
        ip_sock_set_freebind(sock->sk);

        ret = kernel_bind(sock, (struct sockaddr_unsized *)&np->np_sockaddr, len);
        if (ret < 0) {
                pr_err("kernel_bind() failed: %d\n", ret);
                goto fail;
        }

        ret = kernel_listen(sock, backlog);
        if (ret != 0) {
                pr_err("kernel_listen() failed: %d\n", ret);
                goto fail;
        }

        return 0;
fail:
        np->np_socket = NULL;
        sock_release(sock);
        return ret;
}

int iscsi_target_setup_login_socket(
        struct iscsi_np *np,
        struct sockaddr_storage *sockaddr)
{
        struct iscsit_transport *t;
        int rc;

        t = iscsit_get_transport(np->np_network_transport);
        if (!t)
                return -EINVAL;

        rc = t->iscsit_setup_np(np, sockaddr);
        if (rc < 0) {
                iscsit_put_transport(t);
                return rc;
        }

        np->np_transport = t;
        np->enabled = true;
        return 0;
}

int iscsit_accept_np(struct iscsi_np *np, struct iscsit_conn *conn)
{
        struct socket *new_sock, *sock = np->np_socket;
        struct sockaddr_in sock_in;
        struct sockaddr_in6 sock_in6;
        int rc;

        rc = kernel_accept(sock, &new_sock, 0);
        if (rc < 0)
                return rc;

        conn->sock = new_sock;
        conn->login_family = np->np_sockaddr.ss_family;

        if (np->np_sockaddr.ss_family == AF_INET6) {
                memset(&sock_in6, 0, sizeof(struct sockaddr_in6));

                rc = conn->sock->ops->getname(conn->sock,
                                (struct sockaddr *)&sock_in6, 1);
                if (rc >= 0) {
                        if (!ipv6_addr_v4mapped(&sock_in6.sin6_addr)) {
                                memcpy(&conn->login_sockaddr, &sock_in6, sizeof(sock_in6));
                        } else {
                                /* Pretend to be an ipv4 socket */
                                sock_in.sin_family = AF_INET;
                                sock_in.sin_port = sock_in6.sin6_port;
                                memcpy(&sock_in.sin_addr, &sock_in6.sin6_addr.s6_addr32[3], 4);
                                memcpy(&conn->login_sockaddr, &sock_in, sizeof(sock_in));
                        }
                }

                rc = conn->sock->ops->getname(conn->sock,
                                (struct sockaddr *)&sock_in6, 0);
                if (rc >= 0) {
                        if (!ipv6_addr_v4mapped(&sock_in6.sin6_addr)) {
                                memcpy(&conn->local_sockaddr, &sock_in6, sizeof(sock_in6));
                        } else {
                                /* Pretend to be an ipv4 socket */
                                sock_in.sin_family = AF_INET;
                                sock_in.sin_port = sock_in6.sin6_port;
                                memcpy(&sock_in.sin_addr, &sock_in6.sin6_addr.s6_addr32[3], 4);
                                memcpy(&conn->local_sockaddr, &sock_in, sizeof(sock_in));
                        }
                }
        } else {
                memset(&sock_in, 0, sizeof(struct sockaddr_in));

                rc = conn->sock->ops->getname(conn->sock,
                                (struct sockaddr *)&sock_in, 1);
                if (rc >= 0)
                        memcpy(&conn->login_sockaddr, &sock_in, sizeof(sock_in));

                rc = conn->sock->ops->getname(conn->sock,
                                (struct sockaddr *)&sock_in, 0);
                if (rc >= 0)
                        memcpy(&conn->local_sockaddr, &sock_in, sizeof(sock_in));
        }

        return 0;
}

int iscsit_get_login_rx(struct iscsit_conn *conn, struct iscsi_login *login)
{
        struct iscsi_login_req *login_req;
        u32 padding = 0, payload_length;

        if (iscsi_login_rx_data(conn, login->req, ISCSI_HDR_LEN) < 0)
                return -1;

        login_req = (struct iscsi_login_req *)login->req;
        payload_length  = ntoh24(login_req->dlength);
        padding = ((-payload_length) & 3);

        pr_debug("Got Login Command, Flags 0x%02x, ITT: 0x%08x,"
                " CmdSN: 0x%08x, ExpStatSN: 0x%08x, CID: %hu, Length: %u\n",
                login_req->flags, login_req->itt, login_req->cmdsn,
                login_req->exp_statsn, login_req->cid, payload_length);
        /*
         * Setup the initial iscsi_login values from the leading
         * login request PDU.
         */
        if (login->first_request) {
                login_req = (struct iscsi_login_req *)login->req;
                login->leading_connection = (!login_req->tsih) ? 1 : 0;
                login->current_stage    = ISCSI_LOGIN_CURRENT_STAGE(login_req->flags);
                login->version_min      = login_req->min_version;
                login->version_max      = login_req->max_version;
                memcpy(login->isid, login_req->isid, 6);
                login->cmd_sn           = be32_to_cpu(login_req->cmdsn);
                login->init_task_tag    = login_req->itt;
                login->initial_exp_statsn = be32_to_cpu(login_req->exp_statsn);
                login->cid              = be16_to_cpu(login_req->cid);
                login->tsih             = be16_to_cpu(login_req->tsih);
        }

        if (iscsi_target_check_login_request(conn, login) < 0)
                return -1;

        memset(login->req_buf, 0, MAX_KEY_VALUE_PAIRS);
        if (iscsi_login_rx_data(conn, login->req_buf,
                                payload_length + padding) < 0)
                return -1;

        return 0;
}

int iscsit_put_login_tx(struct iscsit_conn *conn, struct iscsi_login *login,
                        u32 length)
{
        if (iscsi_login_tx_data(conn, login->rsp, login->rsp_buf, length) < 0)
                return -1;

        return 0;
}

static int
iscsit_conn_set_transport(struct iscsit_conn *conn, struct iscsit_transport *t)
{
        int rc;

        if (!t->owner) {
                conn->conn_transport = t;
                return 0;
        }

        rc = try_module_get(t->owner);
        if (!rc) {
                pr_err("try_module_get() failed for %s\n", t->name);
                return -EINVAL;
        }

        conn->conn_transport = t;
        return 0;
}

static struct iscsit_conn *iscsit_alloc_conn(struct iscsi_np *np)
{
        struct iscsit_conn *conn;

        conn = kzalloc_obj(struct iscsit_conn);
        if (!conn) {
                pr_err("Could not allocate memory for new connection\n");
                return NULL;
        }
        pr_debug("Moving to TARG_CONN_STATE_FREE.\n");
        conn->conn_state = TARG_CONN_STATE_FREE;

        init_waitqueue_head(&conn->queues_wq);
        INIT_LIST_HEAD(&conn->conn_list);
        INIT_LIST_HEAD(&conn->conn_cmd_list);
        INIT_LIST_HEAD(&conn->immed_queue_list);
        INIT_LIST_HEAD(&conn->response_queue_list);
        init_completion(&conn->conn_post_wait_comp);
        init_completion(&conn->conn_wait_comp);
        init_completion(&conn->conn_wait_rcfr_comp);
        init_completion(&conn->conn_waiting_on_uc_comp);
        init_completion(&conn->conn_logout_comp);
        init_completion(&conn->rx_half_close_comp);
        init_completion(&conn->tx_half_close_comp);
        init_completion(&conn->rx_login_comp);
        spin_lock_init(&conn->cmd_lock);
        spin_lock_init(&conn->conn_usage_lock);
        spin_lock_init(&conn->immed_queue_lock);
        spin_lock_init(&conn->nopin_timer_lock);
        spin_lock_init(&conn->response_queue_lock);
        spin_lock_init(&conn->state_lock);
        spin_lock_init(&conn->login_worker_lock);
        spin_lock_init(&conn->login_timer_lock);

        timer_setup(&conn->nopin_response_timer,
                    iscsit_handle_nopin_response_timeout, 0);
        timer_setup(&conn->nopin_timer, iscsit_handle_nopin_timeout, 0);
        timer_setup(&conn->login_timer, iscsit_login_timeout, 0);

        if (iscsit_conn_set_transport(conn, np->np_transport) < 0)
                goto free_conn;

        conn->conn_ops = kzalloc_obj(struct iscsi_conn_ops);
        if (!conn->conn_ops) {
                pr_err("Unable to allocate memory for struct iscsi_conn_ops.\n");
                goto put_transport;
        }

        if (!zalloc_cpumask_var(&conn->conn_cpumask, GFP_KERNEL)) {
                pr_err("Unable to allocate conn->conn_cpumask\n");
                goto free_conn_ops;
        }

        if (!zalloc_cpumask_var(&conn->allowed_cpumask, GFP_KERNEL)) {
                pr_err("Unable to allocate conn->allowed_cpumask\n");
                goto free_conn_cpumask;
        }

        conn->cmd_cnt = target_alloc_cmd_counter();
        if (!conn->cmd_cnt)
                goto free_conn_allowed_cpumask;

        return conn;

free_conn_allowed_cpumask:
        free_cpumask_var(conn->allowed_cpumask);
free_conn_cpumask:
        free_cpumask_var(conn->conn_cpumask);
free_conn_ops:
        kfree(conn->conn_ops);
put_transport:
        iscsit_put_transport(conn->conn_transport);
free_conn:
        kfree(conn);
        return NULL;
}

void iscsit_free_conn(struct iscsit_conn *conn)
{
        target_free_cmd_counter(conn->cmd_cnt);
        free_cpumask_var(conn->allowed_cpumask);
        free_cpumask_var(conn->conn_cpumask);
        kfree(conn->conn_ops);
        iscsit_put_transport(conn->conn_transport);
        kfree(conn);
}

void iscsi_target_login_sess_out(struct iscsit_conn *conn,
                                 bool zero_tsih, bool new_sess)
{
        if (!new_sess)
                goto old_sess_out;

        pr_err("iSCSI Login negotiation failed.\n");
        iscsit_collect_login_stats(conn, ISCSI_STATUS_CLS_INITIATOR_ERR,
                                   ISCSI_LOGIN_STATUS_INIT_ERR);
        if (!zero_tsih || !conn->sess)
                goto old_sess_out;

        transport_free_session(conn->sess->se_sess);
        ida_free(&sess_ida, conn->sess->session_index);
        kfree(conn->sess->sess_ops);
        kfree(conn->sess);
        conn->sess = NULL;

old_sess_out:
        /*
         * If login negotiation fails check if the Time2Retain timer
         * needs to be restarted.
         */
        if (!zero_tsih && conn->sess) {
                spin_lock_bh(&conn->sess->conn_lock);
                if (conn->sess->session_state == TARG_SESS_STATE_FAILED) {
                        struct se_portal_group *se_tpg =
                                        &conn->tpg->tpg_se_tpg;

                        atomic_set(&conn->sess->session_continuation, 0);
                        spin_unlock_bh(&conn->sess->conn_lock);
                        spin_lock_bh(&se_tpg->session_lock);
                        iscsit_start_time2retain_handler(conn->sess);
                        spin_unlock_bh(&se_tpg->session_lock);
                } else
                        spin_unlock_bh(&conn->sess->conn_lock);
                iscsit_dec_session_usage_count(conn->sess);
        }

        if (conn->param_list) {
                iscsi_release_param_list(conn->param_list);
                conn->param_list = NULL;
        }
        iscsi_target_nego_release(conn);

        if (conn->sock) {
                sock_release(conn->sock);
                conn->sock = NULL;
        }

        if (conn->conn_transport->iscsit_wait_conn)
                conn->conn_transport->iscsit_wait_conn(conn);

        if (conn->conn_transport->iscsit_free_conn)
                conn->conn_transport->iscsit_free_conn(conn);

        iscsit_free_conn(conn);
}

static int __iscsi_target_login_thread(struct iscsi_np *np)
{
        u8 *buffer, zero_tsih = 0;
        int ret = 0, rc;
        struct iscsit_conn *conn = NULL;
        struct iscsi_login *login;
        struct iscsi_portal_group *tpg = NULL;
        struct iscsi_login_req *pdu;
        struct iscsi_tpg_np *tpg_np;
        bool new_sess = false;

        flush_signals(current);

        spin_lock_bh(&np->np_thread_lock);
        if (atomic_dec_if_positive(&np->np_reset_count) >= 0) {
                np->np_thread_state = ISCSI_NP_THREAD_ACTIVE;
                spin_unlock_bh(&np->np_thread_lock);
                complete(&np->np_restart_comp);
                return 1;
        } else if (np->np_thread_state == ISCSI_NP_THREAD_SHUTDOWN) {
                spin_unlock_bh(&np->np_thread_lock);
                goto exit;
        } else {
                np->np_thread_state = ISCSI_NP_THREAD_ACTIVE;
        }
        spin_unlock_bh(&np->np_thread_lock);

        conn = iscsit_alloc_conn(np);
        if (!conn) {
                /* Get another socket */
                return 1;
        }

        rc = np->np_transport->iscsit_accept_np(np, conn);
        if (rc == -ENOSYS) {
                complete(&np->np_restart_comp);
                iscsit_free_conn(conn);
                goto exit;
        } else if (rc < 0) {
                spin_lock_bh(&np->np_thread_lock);
                if (atomic_dec_if_positive(&np->np_reset_count) >= 0) {
                        np->np_thread_state = ISCSI_NP_THREAD_ACTIVE;
                        spin_unlock_bh(&np->np_thread_lock);
                        complete(&np->np_restart_comp);
                        iscsit_free_conn(conn);
                        /* Get another socket */
                        return 1;
                }
                spin_unlock_bh(&np->np_thread_lock);
                iscsit_free_conn(conn);
                return 1;
        }
        /*
         * Perform the remaining iSCSI connection initialization items..
         */
        login = iscsi_login_init_conn(conn);
        if (!login) {
                goto new_sess_out;
        }

        iscsit_start_login_timer(conn, current);

        pr_debug("Moving to TARG_CONN_STATE_XPT_UP.\n");
        conn->conn_state = TARG_CONN_STATE_XPT_UP;
        /*
         * This will process the first login request + payload..
         */
        rc = np->np_transport->iscsit_get_login_rx(conn, login);
        if (rc == 1)
                return 1;
        else if (rc < 0)
                goto new_sess_out;

        buffer = &login->req[0];
        pdu = (struct iscsi_login_req *)buffer;
        /*
         * Used by iscsit_tx_login_rsp() for Login Resonses PDUs
         * when Status-Class != 0.
        */
        conn->login_itt = pdu->itt;

        spin_lock_bh(&np->np_thread_lock);
        if (np->np_thread_state != ISCSI_NP_THREAD_ACTIVE) {
                spin_unlock_bh(&np->np_thread_lock);
                pr_err("iSCSI Network Portal on %pISpc currently not"
                        " active.\n", &np->np_sockaddr);
                iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                ISCSI_LOGIN_STATUS_SVC_UNAVAILABLE);
                goto new_sess_out;
        }
        spin_unlock_bh(&np->np_thread_lock);

        conn->network_transport = np->np_network_transport;

        pr_debug("Received iSCSI login request from %pISpc on %s Network"
                " Portal %pISpc\n", &conn->login_sockaddr, np->np_transport->name,
                &conn->local_sockaddr);

        pr_debug("Moving to TARG_CONN_STATE_IN_LOGIN.\n");
        conn->conn_state        = TARG_CONN_STATE_IN_LOGIN;

        if (iscsi_login_check_initiator_version(conn, pdu->max_version,
                        pdu->min_version) < 0)
                goto new_sess_out;

        zero_tsih = (pdu->tsih == 0x0000);
        if (zero_tsih) {
                /*
                 * This is the leading connection of a new session.
                 * We wait until after authentication to check for
                 * session reinstatement.
                 */
                if (iscsi_login_zero_tsih_s1(conn, buffer) < 0)
                        goto new_sess_out;
        } else {
                /*
                 * Add a new connection to an existing session.
                 * We check for a non-existant session in
                 * iscsi_login_non_zero_tsih_s2() below based
                 * on ISID/TSIH, but wait until after authentication
                 * to check for connection reinstatement, etc.
                 */
                if (iscsi_login_non_zero_tsih_s1(conn, buffer) < 0)
                        goto new_sess_out;
        }
        /*
         * SessionType: Discovery
         *
         *      Locates Default Portal
         *
         * SessionType: Normal
         *
         *      Locates Target Portal from NP -> Target IQN
         */
        rc = iscsi_target_locate_portal(np, conn, login);
        if (rc < 0) {
                tpg = conn->tpg;
                goto new_sess_out;
        }
        login->zero_tsih = zero_tsih;

        if (conn->sess)
                conn->sess->se_sess->sup_prot_ops =
                        conn->conn_transport->iscsit_get_sup_prot_ops(conn);

        tpg = conn->tpg;
        if (!tpg) {
                pr_err("Unable to locate struct iscsit_conn->tpg\n");
                goto new_sess_out;
        }

        if (zero_tsih) {
                if (iscsi_login_zero_tsih_s2(conn) < 0)
                        goto new_sess_out;
        } else {
                if (iscsi_login_non_zero_tsih_s2(conn, buffer) < 0)
                        goto old_sess_out;
        }

        if (conn->conn_transport->iscsit_validate_params) {
                ret = conn->conn_transport->iscsit_validate_params(conn);
                if (ret < 0) {
                        if (zero_tsih)
                                goto new_sess_out;
                        else
                                goto old_sess_out;
                }
        }

        ret = iscsi_target_start_negotiation(login, conn);
        if (ret < 0)
                goto new_sess_out;

        if (ret == 1) {
                tpg_np = conn->tpg_np;

                iscsi_post_login_handler(np, conn, zero_tsih);
                iscsit_deaccess_np(np, tpg, tpg_np);
        }

        tpg = NULL;
        tpg_np = NULL;
        /* Get another socket */
        return 1;

new_sess_out:
        new_sess = true;
old_sess_out:
        iscsit_stop_login_timer(conn);
        tpg_np = conn->tpg_np;
        iscsi_target_login_sess_out(conn, zero_tsih, new_sess);
        new_sess = false;

        if (tpg) {
                iscsit_deaccess_np(np, tpg, tpg_np);
                tpg = NULL;
                tpg_np = NULL;
        }

        return 1;

exit:
        spin_lock_bh(&np->np_thread_lock);
        np->np_thread_state = ISCSI_NP_THREAD_EXIT;
        spin_unlock_bh(&np->np_thread_lock);

        return 0;
}

int iscsi_target_login_thread(void *arg)
{
        struct iscsi_np *np = arg;
        int ret;

        allow_signal(SIGINT);

        while (1) {
                ret = __iscsi_target_login_thread(np);
                /*
                 * We break and exit here unless another sock_accept() call
                 * is expected.
                 */
                if (ret != 1)
                        break;
        }

        while (!kthread_should_stop()) {
                msleep(100);
        }

        return 0;
}