/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2012 The FreeBSD Foundation
 *
 * This software was developed by Edward Tomasz Napierala under sponsorship
 * from the FreeBSD Foundation.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/types.h>
#include <sys/ioctl.h>
#include <stdbool.h>
#include <string.h>
#include <netinet/in.h>

#include "iscsid.h"
#include "iscsi_proto.h"

static struct pdu *
logout_receive(struct connection *conn)
{
        struct pdu *response;
        struct iscsi_bhs_logout_response *bhslr;

        response = pdu_new(conn);
        pdu_receive(response);
        if (response->pdu_bhs->bhs_opcode != ISCSI_BHS_OPCODE_LOGOUT_RESPONSE)
                log_errx(1, "protocol error: received invalid opcode 0x%x",
                    response->pdu_bhs->bhs_opcode);
        bhslr = (struct iscsi_bhs_logout_response *)response->pdu_bhs;
        if (ntohs(bhslr->bhslr_response) != BHSLR_RESPONSE_CLOSED_SUCCESSFULLY)
                log_warnx("received Logout Response with reason %d",
                    ntohs(bhslr->bhslr_response));
        if (ntohl(bhslr->bhslr_statsn) != conn->conn_statsn + 1) {
                log_errx(1, "received Logout PDU with wrong StatSN: "
                    "is %u, should be %u", ntohl(bhslr->bhslr_statsn),
                    conn->conn_statsn + 1);
        }
        conn->conn_statsn = ntohl(bhslr->bhslr_statsn);

        return (response);
}

static struct pdu *
logout_new_request(struct connection *conn)
{
        struct pdu *request;
        struct iscsi_bhs_logout_request *bhslr;

        request = pdu_new(conn);
        bhslr = (struct iscsi_bhs_logout_request *)request->pdu_bhs;
        bhslr->bhslr_opcode = ISCSI_BHS_OPCODE_LOGOUT_REQUEST |
            ISCSI_BHS_OPCODE_IMMEDIATE;
        bhslr->bhslr_reason = BHSLR_REASON_CLOSE_SESSION;
        bhslr->bhslr_reason |= 0x80;
        bhslr->bhslr_initiator_task_tag = 0; /* XXX */
        bhslr->bhslr_cmdsn = 0; /* XXX */
        bhslr->bhslr_expstatsn = htonl(conn->conn_statsn + 1);

        return (request);
}

static void
kernel_add(const struct iscsid_connection *conn, const char *target)
{
        struct iscsi_session_add isa;
        int error;

        memset(&isa, 0, sizeof(isa));
        memcpy(&isa.isa_conf, &conn->conn_conf, sizeof(isa.isa_conf));
        strlcpy(isa.isa_conf.isc_target, target,
            sizeof(isa.isa_conf.isc_target));
        isa.isa_conf.isc_discovery = 0;
        error = ioctl(conn->conn_iscsi_fd, ISCSISADD, &isa);
        if (error != 0)
                log_warn("failed to add %s: ISCSISADD", target);
}

static void
kernel_remove(const struct iscsid_connection *conn)
{
        struct iscsi_session_remove isr;
        int error;

        memset(&isr, 0, sizeof(isr));
        isr.isr_session_id = conn->conn_session_id;
        error = ioctl(conn->conn_iscsi_fd, ISCSISREMOVE, &isr);
        if (error != 0)
                log_warn("ISCSISREMOVE");
}

void
discovery(struct iscsid_connection *conn)
{
        struct pdu *request, *response;
        struct keys *request_keys, *response_keys;
        int i;

        log_debugx("beginning discovery session");
        request_keys = keys_new();
        keys_add(request_keys, "SendTargets", "All");
        text_send_request(&conn->conn, request_keys);
        keys_delete(request_keys);
        request_keys = NULL;

        log_debugx("waiting for Text Response");
        response_keys = text_read_response(&conn->conn);
        for (i = 0; i < KEYS_MAX; i++) {
                if (response_keys->keys_names[i] == NULL)
                        break;

                if (strcmp(response_keys->keys_names[i], "TargetName") != 0)
                        continue;

                log_debugx("adding target %s", response_keys->keys_values[i]);
                /*
                 * XXX: Validate the target name?
                 */
                kernel_add(conn, response_keys->keys_values[i]);
        }
        keys_delete(response_keys);

        log_debugx("removing temporary discovery session");
        kernel_remove(conn);

#ifdef ICL_KERNEL_PROXY
        if (conn->conn_conf.isc_iser == 1) {
                /*
                 * If we're going through the proxy, the kernel already
                 * sent Logout PDU for us and destroyed the session,
                 * so we can't send anything anymore.
                 */
                log_debugx("discovery session done");
                return;
        }
#endif

        log_debugx("discovery done; logging out");
        request = logout_new_request(&conn->conn);
        pdu_send(request);
        pdu_delete(request);
        request = NULL;

        log_debugx("waiting for Logout Response");
        response = logout_receive(&conn->conn);
        pdu_delete(response);

        log_debugx("discovery session done");
}