/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2017 Nexenta Systems, Inc.
 */

#include <sys/cpuvar.h>
#include <sys/types.h>
#include <sys/conf.h>
#include <sys/file.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/modctl.h>
#include <sys/sysmacros.h>
#include <sys/socket.h>
#include <sys/strsubr.h>
#include <inet/tcp.h>
#include <sys/nvpair.h>

#include <sys/stmf.h>
#include <sys/stmf_ioctl.h>
#include <sys/portif.h>
#include <sys/idm/idm.h>
#include <sys/idm/idm_conn_sm.h>
#include <sys/idm/idm_text.h>
#include <sys/idm/idm_so.h>

#include "iscsit_isns.h"
#include "iscsit.h"

#define IPADDRSTRLEN    INET6_ADDRSTRLEN        /* space for ipaddr string */
#define PORTALSTRLEN    (IPADDRSTRLEN+16)       /* add space for :port,tag */

void
iscsit_text_cmd_fini(iscsit_conn_t *ict);

static void
iscsit_bump_ttt(iscsit_conn_t *ict)
{
        /*
         * Set the target task tag. The value will be zero when
         * the connection is created. Increment it and wrap it
         * back to one if we hit the reserved value.
         *
         * The TTT is fabricated since there is no real task associated
         * with a text request. The idm task range is reused here since
         * no real tasks can be started from a discovery session and
         * thus no conflicts are possible.
         */
        if (++ict->ict_text_rsp_ttt == IDM_TASKIDS_MAX)
                ict->ict_text_rsp_ttt = 1;
}

static void
iscsit_text_resp_complete_cb(idm_pdu_t *pdu, idm_status_t status)
{
        iscsit_conn_t *ict = pdu->isp_private;

        idm_pdu_free(pdu);
        if (status != IDM_STATUS_SUCCESS) {
                /*
                 * Could not send the last text response.
                 * Clear any state and bump the TTT so subsequent
                 * requests will not match.
                 */
                iscsit_text_cmd_fini(ict);
                iscsit_bump_ttt(ict);
        }
        iscsit_conn_rele(ict);
}

static void
iscsit_text_reject(idm_pdu_t *req_pdu, uint8_t reason_code)
{
        iscsit_conn_t           *ict = req_pdu->isp_ic->ic_handle;

        /*
         * A reject means abandoning this text request.
         * Cleanup any state from the request and increment the TTT
         * in case the initiator does not get the reject response
         * and attempts to resume this request.
         */
        iscsit_text_cmd_fini(ict);
        iscsit_bump_ttt(ict);
        iscsit_send_reject(ict, req_pdu, reason_code);
        idm_pdu_complete(req_pdu, IDM_STATUS_SUCCESS);

}


/*
 * Add individual <TargetAddress=ipaddr> tuple to the nvlist
 */
static void
iscsit_add_portal(struct sockaddr_storage *ss, int tag, nvlist_t *nv_resp)
{
        char ipaddr[IPADDRSTRLEN];      /* ip address string */
        char ta_value[PORTALSTRLEN];    /* target address value */
        struct sockaddr_in *sin;
        struct sockaddr_in6 *sin6;

        switch (ss->ss_family) {
        case AF_INET:
                sin = (struct sockaddr_in *)ss;
                (void) inet_ntop(AF_INET, &sin->sin_addr, ipaddr,
                    sizeof (ipaddr));
                (void) snprintf(ta_value, sizeof (ta_value), "%s:%d,%d",
                    ipaddr, ntohs(sin->sin_port), tag);
                break;
        case AF_INET6:
                sin6 = (struct sockaddr_in6 *)ss;
                (void) inet_ntop(AF_INET6, &sin6->sin6_addr, ipaddr,
                    sizeof (ipaddr));
                (void) snprintf(ta_value, sizeof (ta_value), "[%s]:%d,%d",
                    ipaddr, ntohs(sin6->sin6_port), tag);
                break;
        default:
                ASSERT(0);
                return;
        }
        (void) nvlist_add_string(nv_resp, "TargetAddress", ta_value);
}

/*
 * Process the special case of the default portal group.
 * Network addresses are obtained from the network stack and
 * require some reformatting.
 */
static void
iscsit_add_default_portals(iscsit_conn_t *ict, idm_addr_list_t *ipaddr_p,
    nvlist_t *nv_resp)
{
        int pass, i;
        idm_addr_t *tip;
        struct sockaddr_storage ss;
        struct sockaddr_in *sin;
        struct sockaddr_in6 *sin6;

        /*
         * If this request was received on one of the portals,
         * output that portal first. Most initiators will try to
         * connect on the first portal in the SendTargets response.
         * For example, this will avoid the confusing situation of a
         * discovery coming in on an IB interface and the initiator
         * then doing the normal login on an ethernet interface.
         */
        sin = (struct sockaddr_in *)&ss;
        sin6 = (struct sockaddr_in6 *)&ss;
        for (pass = 1; pass <= 2; pass++) {
                tip = &ipaddr_p->al_addrs[0];
                for (i = 0; i < ipaddr_p->al_out_cnt; i++, tip++) {
                        /* Convert the address into sockaddr_storage format */
                        switch (tip->a_addr.i_insize) {
                        case sizeof (struct in_addr):
                                sin->sin_family = AF_INET;
                                sin->sin_port = htons(ISCSI_LISTEN_PORT);
                                sin->sin_addr = tip->a_addr.i_addr.in4;
                                break;
                        case sizeof (struct in6_addr):
                                sin6->sin6_family = AF_INET6;
                                sin6->sin6_port = htons(ISCSI_LISTEN_PORT);
                                sin6->sin6_addr = tip->a_addr.i_addr.in6;
                                break;
                        default:
                                ASSERT(0);
                                continue;
                        }
                        switch (pass) {
                        case 1:
                                /*
                                 * On the first pass, skip portals that
                                 * do not match the incoming connection.
                                 */
                                if (idm_ss_compare(&ss, &ict->ict_ic->ic_laddr,
                                    B_TRUE, B_TRUE) != 0)
                                        continue;
                                break;
                        case 2:
                                /*
                                 * On the second pass, process the
                                 * remaining portals.
                                 */
                                if (idm_ss_compare(&ss, &ict->ict_ic->ic_laddr,
                                    B_TRUE, B_TRUE) == 0)
                                        continue;
                                break;
                        }
                        /*
                         * Add portal to the response list.
                         * By convention, the default portal group tag == 1
                         */
                        iscsit_add_portal(&ss, 1, nv_resp);
                }
        }
}

/*
 * Process a portal group from the configuration database.
 */
static void
iscsit_add_portals(iscsit_conn_t *ict, iscsit_tpgt_t *tpg_list,
    nvlist_t *nv_resp)
{
        int pass;
        iscsit_portal_t *portal, *next_portal;
        iscsit_tpg_t *tpg;
        struct sockaddr_storage *ss;

        /*
         * As with the default portal group, output the portal used by
         * the incoming request first.
         */
        tpg = tpg_list->tpgt_tpg;
        for (pass = 1; pass <= 2; pass++) {
                for (portal = avl_first(&tpg->tpg_portal_list);
                    portal != NULL;
                    portal = next_portal) {

                        next_portal = AVL_NEXT(&tpg->tpg_portal_list, portal);
                        ss = &portal->portal_addr;
                        switch (pass) {
                        case 1:
                                /*
                                 * On the first pass, skip portals that
                                 * do not match the incoming connection.
                                 */
                                if (idm_ss_compare(ss, &ict->ict_ic->ic_laddr,
                                    B_TRUE, B_TRUE) != 0)
                                        continue;
                                break;
                        case 2:
                                /*
                                 * On the second pass, process the
                                 * remaining portals.
                                 */
                                if (idm_ss_compare(ss, &ict->ict_ic->ic_laddr,
                                    B_TRUE, B_TRUE) == 0)
                                        continue;
                                break;
                        }
                        /* Add portal to the response list */
                        iscsit_add_portal(ss, tpg_list->tpgt_tag, nv_resp);
                }
        }
}

/*
 * Process all the portal groups bound to a particular target.
 */
static void
iscsit_add_tpgs(iscsit_conn_t *ict, iscsit_tgt_t *target,
    idm_addr_list_t *ipaddr_p,  nvlist_t *nv_resp)
{
        iscsit_tpgt_t *tpg_list;

        /*
         * Look through the portal groups associated with this target.
         */
        mutex_enter(&target->target_mutex);
        tpg_list = avl_first(&target->target_tpgt_list);

        /* check for the default portal group */
        if (tpg_list->tpgt_tpg == iscsit_global.global_default_tpg) {
                /*
                 * The default portal group is a special case and will
                 * return all reasonable interfaces on this node.
                 *
                 * A target cannot be bound to other portal groups
                 * if it is bound to the default portal group.
                 */
                ASSERT(AVL_NEXT(&target->target_tpgt_list, tpg_list) == NULL);

                if (ipaddr_p != NULL) {
                        /* convert the ip address list to nvlist format */
                        iscsit_add_default_portals(ict, ipaddr_p, nv_resp);
                }
                mutex_exit(&target->target_mutex);
                return;
        }

        /*
         * Not the default portal group - process the user defined tpgs
         */
        ASSERT(tpg_list != NULL);
        while (tpg_list != NULL) {

                ASSERT(tpg_list->tpgt_tpg != iscsit_global.global_default_tpg);

                /*
                 * Found a defined portal group - add each portal address.
                 * As with the default portal group, make 2 passes over
                 * the addresses in order to output the connection
                 * address first.
                 */
                iscsit_add_portals(ict, tpg_list, nv_resp);

                tpg_list = AVL_NEXT(&target->target_tpgt_list, tpg_list);
        }
        mutex_exit(&target->target_mutex);
}

#ifdef DEBUG
/*
 * To test with smaller PDUs in order to force multi-PDU responses,
 * set this value such that: 0 < test_max_len < 8192
 */
uint32_t iscsit_text_max_len = ISCSI_DEFAULT_MAX_RECV_SEG_LEN;
#endif

/*
 * Format a text response PDU from the text buffer and send it.
 */
static void
iscsit_send_next_text_response(iscsit_conn_t *ict, idm_pdu_t *rx_pdu)
{
        iscsi_text_hdr_t *th_req = (iscsi_text_hdr_t *)rx_pdu->isp_hdr;
        iscsi_text_rsp_hdr_t *th_resp;
        idm_pdu_t       *resp;
        uint32_t        len, remainder, max_len;
        char            *base;
        boolean_t       final;

        max_len = ISCSI_DEFAULT_MAX_RECV_SEG_LEN;
#ifdef DEBUG
        if (iscsit_text_max_len > 0 && iscsit_text_max_len < max_len)
                max_len = iscsit_text_max_len;
#endif
        do {
                remainder = ict->ict_text_rsp_valid_len - ict->ict_text_rsp_off;
                if (remainder <= max_len) {
                        len = remainder;
                        final = B_TRUE;
                } else {
                        len = max_len;
                        final = B_FALSE;
                }
                /*
                 * Allocate a PDU and copy in text response buffer
                 */
                resp = idm_pdu_alloc(sizeof (iscsi_hdr_t), len);
                idm_pdu_init(resp, ict->ict_ic, ict,
                    iscsit_text_resp_complete_cb);
                /* Advance the StatSN for each Text Response sent */
                resp->isp_flags |= IDM_PDU_SET_STATSN | IDM_PDU_ADVANCE_STATSN;
                base = ict->ict_text_rsp_buf + ict->ict_text_rsp_off;
                bcopy(base, resp->isp_data, len);
                /*
                 * Fill in the response header
                 */
                th_resp = (iscsi_text_rsp_hdr_t *)resp->isp_hdr;
                bzero(th_resp, sizeof (*th_resp));
                th_resp->opcode = ISCSI_OP_TEXT_RSP;
                th_resp->itt = th_req->itt;
                hton24(th_resp->dlength, len);
                if (final) {
                        th_resp->flags = ISCSI_FLAG_FINAL;
                        th_resp->ttt = ISCSI_RSVD_TASK_TAG;
                        kmem_free(ict->ict_text_rsp_buf, ict->ict_text_rsp_len);
                        ict->ict_text_rsp_buf = NULL;
                        ict->ict_text_rsp_len = 0;
                        ict->ict_text_rsp_valid_len = 0;
                        ict->ict_text_rsp_off = 0;
                } else {
                        th_resp->flags = ISCSI_FLAG_TEXT_CONTINUE;
                        th_resp->ttt = ict->ict_text_rsp_ttt;
                        ict->ict_text_rsp_off += len;
                }
                /* Send the response on its way */
                iscsit_conn_hold(ict);
                iscsit_pdu_tx(resp);
        } while (!final);
        /* Free the request pdu */
        idm_pdu_complete(rx_pdu, IDM_STATUS_SUCCESS);
}

/*
 * Clean-up the text buffer if it exists.
 */
void
iscsit_text_cmd_fini(iscsit_conn_t *ict)
{
        if (ict->ict_text_rsp_buf != NULL) {
                ASSERT(ict->ict_text_rsp_len != 0);
                kmem_free(ict->ict_text_rsp_buf, ict->ict_text_rsp_len);
        }
        ict->ict_text_rsp_buf = NULL;
        ict->ict_text_rsp_len = 0;
        ict->ict_text_rsp_valid_len = 0;
        ict->ict_text_rsp_off = 0;
}

/*
 * Process an iSCSI text command.
 *
 * This code only handles the common case of a text command
 * containing the single tuple SendTargets=All issued during
 * a discovery session. The request will always arrive in a
 * single PDU, but the response may span multiple PDUs if the
 * configuration is large. I.e. many targets and portals.
 *
 * The request is checked for correctness and then the response
 * is generated from the global target into nvlist format. Then
 * the nvlist is reformatted into idm textbuf format which reflects
 * the iSCSI defined <name=value> specification. Finally, the
 * textbuf is sent to the initiator in one or more text response PDUs
 */
void
iscsit_pdu_op_text_cmd(iscsit_conn_t *ict, idm_pdu_t *rx_pdu)
{
        iscsi_text_hdr_t *th_req = (iscsi_text_hdr_t *)rx_pdu->isp_hdr;
        nvlist_t *nv_resp;
        char *kv_pair;
        int flags;
        char *textbuf;
        int textbuflen;
        int validlen;
        int rc;

        flags =  th_req->flags;
        if ((flags & ISCSI_FLAG_FINAL) != ISCSI_FLAG_FINAL) {
                /* Cannot handle multi-PDU requests now */
                iscsit_text_reject(rx_pdu, ISCSI_REJECT_CMD_NOT_SUPPORTED);
                return;
        }
        if (th_req->ttt != ISCSI_RSVD_TASK_TAG) {
                /*
                 * This is the initiator acknowledging our last PDU and
                 * indicating it is ready for the next PDU in the sequence.
                 */
                /*
                 * There can only be one outstanding text request on a
                 * connection. Make sure this one PDU has the current TTT.
                 */
                /* XXX combine the following 3 checks after testing */
                if (th_req->ttt != ict->ict_text_rsp_ttt) {
                        /* Not part of this sequence */
                        iscsit_text_reject(rx_pdu,
                            ISCSI_REJECT_CMD_NOT_SUPPORTED);
                        return;
                }
                /*
                 * ITT should match what was saved from first PDU.
                 */
                if (th_req->itt != ict->ict_text_req_itt) {
                        /* Not part of this sequence */
                        iscsit_text_reject(rx_pdu,
                            ISCSI_REJECT_CMD_NOT_SUPPORTED);
                        return;
                }
                /*
                 * Cannot deal with more key/value pairs now.
                 */
                if (rx_pdu->isp_datalen != 0) {
                        iscsit_text_reject(rx_pdu,
                            ISCSI_REJECT_CMD_NOT_SUPPORTED);
                        return;
                }
                iscsit_send_next_text_response(ict, rx_pdu);
                return;
        }

        /*
         * Initiator has started a new text request. Only
         * one can be active at a time, so abandon any previous
         * text request on this connection.
         */
        iscsit_text_cmd_fini(ict);

        /* Set the target task tag. */
        iscsit_bump_ttt(ict);

        /* Save the initiator task tag */
        ict->ict_text_req_itt = th_req->itt;

        /*
         * Make sure this is a proper SendTargets request
         */
        textbuf = (char *)rx_pdu->isp_data;
        textbuflen = rx_pdu->isp_datalen;
        kv_pair = "SendTargets=All";
        if (textbuflen >= strlen(kv_pair) &&
            strcmp(kv_pair, textbuf) == 0 &&
            ict->ict_op.op_discovery_session == B_TRUE) {
                /*
                 * Most common case of SendTargets=All during discovery.
                 */
                idm_addr_list_t *ipaddr_p;
                iscsit_tgt_t *tgt, *ntgt;
                int ipsize;


                /* Create an nvlist for response */
                if (nvlist_alloc(&nv_resp, 0, KM_SLEEP) != 0) {
                        iscsit_text_reject(rx_pdu,
                            ISCSI_REJECT_CMD_NOT_SUPPORTED);
                        return;
                }

                /* Get the list of local interface addresses */
                ipsize = idm_get_ipaddr(&ipaddr_p);

                /* Add targets to the response list */
                ISCSIT_GLOBAL_LOCK(RW_READER);
                for (tgt = avl_first(&iscsit_global.global_target_list);
                    tgt != NULL; tgt = ntgt) {
                        struct sockaddr_storage v4sa, *sa;
                        iscsit_tgt_state_t state;
                        iscsit_portal_t *portal;
                        iscsit_tpgt_t *tpgt;

                        ntgt = AVL_NEXT(&iscsit_global.global_target_list, tgt);

                        /* Only report online and onlining targets */
                        state = tgt->target_state;
                        if (state != TS_ONLINING && state != TS_ONLINE &&
                            state != TS_STMF_ONLINE)
                                continue;

                        /*
                         * Report target if:
                         * - it is bound to default TPG
                         * - one of the addresses of TPGs the target is bound
                         *   to matches incoming connection dst address
                         */
                        sa = &ict->ict_ic->ic_laddr;
                        mutex_enter(&tgt->target_mutex);
                        tpgt = avl_first(&tgt->target_tpgt_list);
                        if (!(IS_DEFAULT_TPGT(tpgt))) {
                                portal = iscsit_tgt_lookup_portal(tgt, sa,
                                    &tpgt);
                                if (portal == NULL &&
                                    iscsit_is_v4_mapped(sa, &v4sa)) {
                                        portal = iscsit_tgt_lookup_portal(tgt,
                                            &v4sa, &tpgt);
                                }
                                if (portal == NULL) {
                                        mutex_exit(&tgt->target_mutex);
                                        continue;
                                }
                                iscsit_portal_rele(portal);
                                iscsit_tpgt_rele(tpgt);
                        }
                        mutex_exit(&tgt->target_mutex);

                        if (nvlist_add_string(nv_resp, "TargetName",
                            tgt->target_name) == 0) {
                                /* Add the portal groups bound to this target */
                                iscsit_add_tpgs(ict, tgt, ipaddr_p, nv_resp);
                        }
                }
                ISCSIT_GLOBAL_UNLOCK();
                if (ipsize > 0)
                        kmem_free(ipaddr_p, ipsize);

                /* Convert the response nvlist into an idm text buffer */
                textbuf = 0;
                textbuflen = 0;
                validlen = 0;
                rc = idm_nvlist_to_textbuf(nv_resp, &textbuf,
                    &textbuflen, &validlen);
                nvlist_free(nv_resp);
                if (rc != 0) {
                        if (textbuf && textbuflen)
                                kmem_free(textbuf, textbuflen);
                        iscsit_text_reject(rx_pdu,
                            ISCSI_REJECT_CMD_NOT_SUPPORTED);
                        return;
                }
                ict->ict_text_rsp_buf = textbuf;
                ict->ict_text_rsp_len = textbuflen;
                ict->ict_text_rsp_valid_len = validlen;
                ict->ict_text_rsp_off = 0;
                iscsit_send_next_text_response(ict, rx_pdu);
        } else {
                /*
                 * Other cases to handle
                 *    Discovery session:
                 *      SendTargets=<target_name>
                 *    Normal session
                 *      SendTargets=<NULL> - assume target name of session
                 *    All others
                 *      Error
                 */
                iscsit_text_reject(rx_pdu, ISCSI_REJECT_CMD_NOT_SUPPORTED);
                return;
        }
}