/*-
 * 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.
 */

/*
 * CTL frontend for the iSCSI protocol.
 */

#include <sys/param.h>
#include <sys/capsicum.h>
#include <sys/condvar.h>
#include <sys/endian.h>
#include <sys/file.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/sbuf.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <sys/unistd.h>
#include <sys/nv.h>
#include <sys/dnv.h>
#include <vm/uma.h>

#include <cam/scsi/scsi_all.h>
#include <cam/scsi/scsi_da.h>
#include <cam/ctl/ctl_io.h>
#include <cam/ctl/ctl.h>
#include <cam/ctl/ctl_backend.h>
#include <cam/ctl/ctl_error.h>
#include <cam/ctl/ctl_frontend.h>
#include <cam/ctl/ctl_debug.h>
#include <cam/ctl/ctl_ha.h>
#include <cam/ctl/ctl_ioctl.h>
#include <cam/ctl/ctl_private.h>

#include <dev/iscsi/icl.h>
#include <dev/iscsi/icl_wrappers.h>
#include <dev/iscsi/iscsi_proto.h>
#include <cam/ctl/ctl_frontend_iscsi.h>

#ifdef ICL_KERNEL_PROXY
#include <sys/socketvar.h>
#endif

#ifdef ICL_KERNEL_PROXY
FEATURE(cfiscsi_kernel_proxy, "iSCSI target built with ICL_KERNEL_PROXY");
#endif

/* Used for internal nexus reset task. */
#define ISCSI_BHS_OPCODE_INTERNAL       0x3e

static MALLOC_DEFINE(M_CFISCSI, "cfiscsi", "Memory used for CTL iSCSI frontend");
static uma_zone_t cfiscsi_data_wait_zone;

SYSCTL_NODE(_kern_cam_ctl, OID_AUTO, iscsi, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
    "CAM Target Layer iSCSI Frontend");
static int debug = 1;
SYSCTL_INT(_kern_cam_ctl_iscsi, OID_AUTO, debug, CTLFLAG_RWTUN,
    &debug, 1, "Enable debug messages");
static int ping_timeout = 5;
SYSCTL_INT(_kern_cam_ctl_iscsi, OID_AUTO, ping_timeout, CTLFLAG_RWTUN,
    &ping_timeout, 5, "Interval between ping (NOP-Out) requests, in seconds");
static int login_timeout = 60;
SYSCTL_INT(_kern_cam_ctl_iscsi, OID_AUTO, login_timeout, CTLFLAG_RWTUN,
    &login_timeout, 60, "Time to wait for ctld(8) to finish Login Phase, in seconds");
static int maxtags = 256;
SYSCTL_INT(_kern_cam_ctl_iscsi, OID_AUTO, maxtags, CTLFLAG_RWTUN,
    &maxtags, 0, "Max number of requests queued by initiator");

#define CFISCSI_DEBUG(X, ...)                                           \
        do {                                                            \
                if (debug > 1) {                                        \
                        printf("%s: " X "\n",                           \
                            __func__, ## __VA_ARGS__);                  \
                }                                                       \
        } while (0)

#define CFISCSI_WARN(X, ...)                                            \
        do {                                                            \
                if (debug > 0) {                                        \
                        printf("WARNING: %s: " X "\n",                  \
                            __func__, ## __VA_ARGS__);                  \
                }                                                       \
        } while (0)

#define CFISCSI_SESSION_DEBUG(S, X, ...)                                \
        do {                                                            \
                if (debug > 1) {                                        \
                        printf("%s: %s (%s): " X "\n",                  \
                            __func__, S->cs_initiator_addr,             \
                            S->cs_initiator_name, ## __VA_ARGS__);      \
                }                                                       \
        } while (0)

#define CFISCSI_SESSION_WARN(S, X, ...)                                 \
        do  {                                                           \
                if (debug > 0) {                                        \
                        printf("WARNING: %s (%s): " X "\n",             \
                            S->cs_initiator_addr,                       \
                            S->cs_initiator_name, ## __VA_ARGS__);      \
                }                                                       \
        } while (0)

#define CFISCSI_SESSION_LOCK(X)         mtx_lock(&X->cs_lock)
#define CFISCSI_SESSION_UNLOCK(X)       mtx_unlock(&X->cs_lock)
#define CFISCSI_SESSION_LOCK_ASSERT(X)  mtx_assert(&X->cs_lock, MA_OWNED)

#define CONN_SESSION(X)                 ((struct cfiscsi_session *)(X)->ic_prv0)
#define PDU_SESSION(X)                  CONN_SESSION((X)->ip_conn)

struct cfiscsi_priv {
        void            *request;
        uint32_t         expdatasn;
        uint32_t         r2tsn;
};
#define PRIV(io)        \
    ((struct cfiscsi_priv *)&(io)->io_hdr.ctl_private[CTL_PRIV_FRONTEND])
#define PRIV_REQUEST(io)                PRIV(io)->request
#define PRIV_EXPDATASN(io)              PRIV(io)->expdatasn
#define PRIV_R2TSN(io)                  PRIV(io)->r2tsn

static int      cfiscsi_init(void);
static int      cfiscsi_shutdown(void);
static void     cfiscsi_online(void *arg);
static void     cfiscsi_offline(void *arg);
static int      cfiscsi_info(void *arg, struct sbuf *sb);
static int      cfiscsi_ioctl(struct cdev *dev,
                    u_long cmd, caddr_t addr, int flag, struct thread *td);
static void     cfiscsi_datamove(union ctl_io *io);
static void     cfiscsi_datamove_in(union ctl_io *io);
static void     cfiscsi_datamove_out(union ctl_io *io);
static void     cfiscsi_done(union ctl_io *io);
static bool     cfiscsi_pdu_update_cmdsn(const struct icl_pdu *request);
static void     cfiscsi_pdu_handle_nop_out(struct icl_pdu *request);
static void     cfiscsi_pdu_handle_scsi_command(struct icl_pdu *request);
static void     cfiscsi_pdu_handle_task_request(struct icl_pdu *request);
static void     cfiscsi_pdu_handle_data_out(struct icl_pdu *request);
static void     cfiscsi_pdu_handle_logout_request(struct icl_pdu *request);
static void     cfiscsi_session_terminate(struct cfiscsi_session *cs);
static struct cfiscsi_data_wait *cfiscsi_data_wait_new(
                    struct cfiscsi_session *cs, union ctl_io *io,
                    uint32_t initiator_task_tag,
                    uint32_t *target_transfer_tagp);
static void     cfiscsi_data_wait_free(struct cfiscsi_session *cs,
                    struct cfiscsi_data_wait *cdw);
static struct cfiscsi_target    *cfiscsi_target_find(struct cfiscsi_softc
                    *softc, const char *name, uint16_t tag);
static struct cfiscsi_target    *cfiscsi_target_find_or_create(
    struct cfiscsi_softc *softc, const char *name, const char *alias,
    uint16_t tag);
static void     cfiscsi_target_release(struct cfiscsi_target *ct);
static void     cfiscsi_session_delete(struct cfiscsi_session *cs);

static struct cfiscsi_softc cfiscsi_softc;

static struct ctl_frontend cfiscsi_frontend =
{
        .name = "iscsi",
        .init = cfiscsi_init,
        .ioctl = cfiscsi_ioctl,
        .shutdown = cfiscsi_shutdown,
};
CTL_FRONTEND_DECLARE(cfiscsi, cfiscsi_frontend);
MODULE_DEPEND(cfiscsi, icl, 1, 1, 1);

static struct icl_pdu *
cfiscsi_pdu_new_response(struct icl_pdu *request, int flags)
{

        return (icl_pdu_new(request->ip_conn, flags));
}

static bool
cfiscsi_pdu_update_cmdsn(const struct icl_pdu *request)
{
        const struct iscsi_bhs_scsi_command *bhssc;
        struct cfiscsi_session *cs;
        uint32_t cmdsn, curcmdsn;

        cs = PDU_SESSION(request);

        /*
         * Every incoming PDU - not just NOP-Out - resets the ping timer.
         * The purpose of the timeout is to reset the connection when it stalls;
         * we don't want this to happen when NOP-In or NOP-Out ends up delayed
         * in some queue.
         */
        cs->cs_timeout = 0;

        /*
         * Immediate commands carry cmdsn, but it is neither incremented nor
         * verified.
         */
        if (request->ip_bhs->bhs_opcode & ISCSI_BHS_OPCODE_IMMEDIATE)
                return (false);

        /*
         * Data-Out PDUs don't contain CmdSN.
         */
        if (request->ip_bhs->bhs_opcode == ISCSI_BHS_OPCODE_SCSI_DATA_OUT)
                return (false);

        /*
         * We're only using fields common for all the request
         * (initiator -> target) PDUs.
         */
        bhssc = (const struct iscsi_bhs_scsi_command *)request->ip_bhs;
        curcmdsn = cmdsn = ntohl(bhssc->bhssc_cmdsn);

        /*
         * Increment session cmdsn and exit if we received the expected value.
         */
        do {
                if (atomic_fcmpset_32(&cs->cs_cmdsn, &curcmdsn, cmdsn + 1))
                        return (false);
        } while (curcmdsn == cmdsn);

        /*
         * The target MUST silently ignore any non-immediate command outside
         * of this range.
         */
        if (ISCSI_SNLT(cmdsn, curcmdsn) ||
            ISCSI_SNGT(cmdsn, curcmdsn - 1 + maxtags)) {
                CFISCSI_SESSION_WARN(cs, "received PDU with CmdSN %u, "
                    "while expected %u", cmdsn, curcmdsn);
                return (true);
        }

        /*
         * We don't support multiple connections now, so any discontinuity in
         * CmdSN means lost PDUs.  Since we don't support PDU retransmission --
         * terminate the connection.
         */
        CFISCSI_SESSION_WARN(cs, "received PDU with CmdSN %u, "
            "while expected %u; dropping connection",
            cmdsn, curcmdsn);
        cfiscsi_session_terminate(cs);
        return (true);
}

static void
cfiscsi_pdu_handle(struct icl_pdu *request)
{
        struct cfiscsi_session *cs;
        bool ignore;

        cs = PDU_SESSION(request);

        ignore = cfiscsi_pdu_update_cmdsn(request);
        if (ignore) {
                icl_pdu_free(request);
                return;
        }

        /*
         * Handle the PDU; this includes e.g. receiving the remaining
         * part of PDU and submitting the SCSI command to CTL
         * or queueing a reply.  The handling routine is responsible
         * for freeing the PDU when it's no longer needed.
         */
        switch (request->ip_bhs->bhs_opcode &
            ~ISCSI_BHS_OPCODE_IMMEDIATE) {
        case ISCSI_BHS_OPCODE_NOP_OUT:
                cfiscsi_pdu_handle_nop_out(request);
                break;
        case ISCSI_BHS_OPCODE_SCSI_COMMAND:
                cfiscsi_pdu_handle_scsi_command(request);
                break;
        case ISCSI_BHS_OPCODE_TASK_REQUEST:
                cfiscsi_pdu_handle_task_request(request);
                break;
        case ISCSI_BHS_OPCODE_SCSI_DATA_OUT:
                cfiscsi_pdu_handle_data_out(request);
                break;
        case ISCSI_BHS_OPCODE_LOGOUT_REQUEST:
                cfiscsi_pdu_handle_logout_request(request);
                break;
        default:
                CFISCSI_SESSION_WARN(cs, "received PDU with unsupported "
                    "opcode 0x%x; dropping connection",
                    request->ip_bhs->bhs_opcode);
                icl_pdu_free(request);
                cfiscsi_session_terminate(cs);
        }

}

static void
cfiscsi_receive_callback(struct icl_pdu *request)
{
#ifdef ICL_KERNEL_PROXY
        struct cfiscsi_session *cs;

        cs = PDU_SESSION(request);
        if (cs->cs_waiting_for_ctld || cs->cs_login_phase) {
                if (cs->cs_login_pdu == NULL)
                        cs->cs_login_pdu = request;
                else
                        icl_pdu_free(request);
                cv_signal(&cs->cs_login_cv);
                return;
        }
#endif

        cfiscsi_pdu_handle(request);
}

static void
cfiscsi_error_callback(struct icl_conn *ic)
{
        struct cfiscsi_session *cs;

        cs = CONN_SESSION(ic);

        CFISCSI_SESSION_WARN(cs, "connection error; dropping connection");
        cfiscsi_session_terminate(cs);
}

static int
cfiscsi_pdu_prepare(struct icl_pdu *response)
{
        struct cfiscsi_session *cs;
        struct iscsi_bhs_scsi_response *bhssr;
        bool advance_statsn = true;
        uint32_t cmdsn;

        cs = PDU_SESSION(response);

        CFISCSI_SESSION_LOCK_ASSERT(cs);

        /*
         * We're only using fields common for all the response
         * (target -> initiator) PDUs.
         */
        bhssr = (struct iscsi_bhs_scsi_response *)response->ip_bhs;

        /*
         * 10.8.3: "The StatSN for this connection is not advanced
         * after this PDU is sent."
         */
        if (bhssr->bhssr_opcode == ISCSI_BHS_OPCODE_R2T)
                advance_statsn = false;

        /*
         * 10.19.2: "However, when the Initiator Task Tag is set to 0xffffffff,
         * StatSN for the connection is not advanced after this PDU is sent."
         */
        if (bhssr->bhssr_opcode == ISCSI_BHS_OPCODE_NOP_IN && 
            bhssr->bhssr_initiator_task_tag == 0xffffffff)
                advance_statsn = false;

        /*
         * See the comment below - StatSN is not meaningful and must
         * not be advanced.
         */
        if (bhssr->bhssr_opcode == ISCSI_BHS_OPCODE_SCSI_DATA_IN &&
            (bhssr->bhssr_flags & BHSDI_FLAGS_S) == 0)
                advance_statsn = false;

        /*
         * 10.7.3: "The fields StatSN, Status, and Residual Count
         * only have meaningful content if the S bit is set to 1."
         */
        if (bhssr->bhssr_opcode != ISCSI_BHS_OPCODE_SCSI_DATA_IN ||
            (bhssr->bhssr_flags & BHSDI_FLAGS_S))
                bhssr->bhssr_statsn = htonl(cs->cs_statsn);
        cmdsn = cs->cs_cmdsn;
        bhssr->bhssr_expcmdsn = htonl(cmdsn);
        bhssr->bhssr_maxcmdsn = htonl(cmdsn - 1 +
            imax(0, maxtags - cs->cs_outstanding_ctl_pdus));

        if (advance_statsn)
                cs->cs_statsn++;

        return (0);
}

static void
cfiscsi_pdu_queue(struct icl_pdu *response)
{
        struct cfiscsi_session *cs;

        cs = PDU_SESSION(response);

        CFISCSI_SESSION_LOCK(cs);
        cfiscsi_pdu_prepare(response);
        icl_pdu_queue(response);
        CFISCSI_SESSION_UNLOCK(cs);
}

 static void
cfiscsi_pdu_queue_cb(struct icl_pdu *response, icl_pdu_cb cb)
{
        struct cfiscsi_session *cs = PDU_SESSION(response);

        CFISCSI_SESSION_LOCK(cs);
        cfiscsi_pdu_prepare(response);
        icl_pdu_queue_cb(response, cb);
        CFISCSI_SESSION_UNLOCK(cs);
}

static void
cfiscsi_pdu_handle_nop_out(struct icl_pdu *request)
{
        struct cfiscsi_session *cs;
        struct iscsi_bhs_nop_out *bhsno;
        struct iscsi_bhs_nop_in *bhsni;
        struct icl_pdu *response;
        void *data = NULL;
        size_t datasize;
        int error;

        cs = PDU_SESSION(request);
        bhsno = (struct iscsi_bhs_nop_out *)request->ip_bhs;

        if (bhsno->bhsno_initiator_task_tag == 0xffffffff) {
                /*
                 * Nothing to do, iscsi_pdu_update_statsn() already
                 * zeroed the timeout.
                 */
                icl_pdu_free(request);
                return;
        }

        datasize = icl_pdu_data_segment_length(request);
        if (datasize > 0) {
                data = malloc(datasize, M_CFISCSI, M_NOWAIT | M_ZERO);
                if (data == NULL) {
                        CFISCSI_SESSION_WARN(cs, "failed to allocate memory; "
                            "dropping connection");
                        icl_pdu_free(request);
                        cfiscsi_session_terminate(cs);
                        return;
                }
                icl_pdu_get_data(request, 0, data, datasize);
        }

        response = cfiscsi_pdu_new_response(request, M_NOWAIT);
        if (response == NULL) {
                CFISCSI_SESSION_WARN(cs, "failed to allocate memory; "
                    "droppping connection");
                free(data, M_CFISCSI);
                icl_pdu_free(request);
                cfiscsi_session_terminate(cs);
                return;
        }
        bhsni = (struct iscsi_bhs_nop_in *)response->ip_bhs;
        bhsni->bhsni_opcode = ISCSI_BHS_OPCODE_NOP_IN;
        bhsni->bhsni_flags = 0x80;
        bhsni->bhsni_initiator_task_tag = bhsno->bhsno_initiator_task_tag;
        bhsni->bhsni_target_transfer_tag = 0xffffffff;
        if (datasize > 0) {
                error = icl_pdu_append_data(response, data, datasize, M_NOWAIT);
                if (error != 0) {
                        CFISCSI_SESSION_WARN(cs, "failed to allocate memory; "
                            "dropping connection");
                        free(data, M_CFISCSI);
                        icl_pdu_free(request);
                        icl_pdu_free(response);
                        cfiscsi_session_terminate(cs);
                        return;
                }
                free(data, M_CFISCSI);
        }

        icl_pdu_free(request);
        cfiscsi_pdu_queue(response);
}

static void
cfiscsi_pdu_handle_scsi_command(struct icl_pdu *request)
{
        struct iscsi_bhs_scsi_command *bhssc;
        struct cfiscsi_session *cs;
        union ctl_io *io;
        int error;

        cs = PDU_SESSION(request);
        bhssc = (struct iscsi_bhs_scsi_command *)request->ip_bhs;
        //CFISCSI_SESSION_DEBUG(cs, "initiator task tag 0x%x",
        //    bhssc->bhssc_initiator_task_tag);

        if (request->ip_data_len > 0 && cs->cs_immediate_data == false) {
                CFISCSI_SESSION_WARN(cs, "unsolicited data with "
                    "ImmediateData=No; dropping connection");
                icl_pdu_free(request);
                cfiscsi_session_terminate(cs);
                return;
        }
        io = ctl_alloc_io(cs->cs_target->ct_port.ctl_pool_ref);
        ctl_zero_io(io);
        PRIV_REQUEST(io) = request;
        io->io_hdr.io_type = CTL_IO_SCSI;
        io->io_hdr.nexus.initid = cs->cs_ctl_initid;
        io->io_hdr.nexus.targ_port = cs->cs_target->ct_port.targ_port;
        io->io_hdr.nexus.targ_lun = ctl_decode_lun(be64toh(bhssc->bhssc_lun));
        io->scsiio.priority = (bhssc->bhssc_pri & BHSSC_PRI_MASK) >>
            BHSSC_PRI_SHIFT;
        io->scsiio.tag_num = bhssc->bhssc_initiator_task_tag;
        switch ((bhssc->bhssc_flags & BHSSC_FLAGS_ATTR)) {
        case BHSSC_FLAGS_ATTR_UNTAGGED:
                io->scsiio.tag_type = CTL_TAG_UNTAGGED;
                break;
        case BHSSC_FLAGS_ATTR_SIMPLE:
                io->scsiio.tag_type = CTL_TAG_SIMPLE;
                break;
        case BHSSC_FLAGS_ATTR_ORDERED:
                io->scsiio.tag_type = CTL_TAG_ORDERED;
                break;
        case BHSSC_FLAGS_ATTR_HOQ:
                io->scsiio.tag_type = CTL_TAG_HEAD_OF_QUEUE;
                break;
        case BHSSC_FLAGS_ATTR_ACA:
                io->scsiio.tag_type = CTL_TAG_ACA;
                break;
        default:
                io->scsiio.tag_type = CTL_TAG_UNTAGGED;
                CFISCSI_SESSION_WARN(cs, "unhandled tag type %d",
                    bhssc->bhssc_flags & BHSSC_FLAGS_ATTR);
                break;
        }
        io->scsiio.cdb_len = sizeof(bhssc->bhssc_cdb); /* Which is 16. */
        memcpy(io->scsiio.cdb, bhssc->bhssc_cdb, sizeof(bhssc->bhssc_cdb));
        refcount_acquire(&cs->cs_outstanding_ctl_pdus);
        error = ctl_run(io);
        if (error != CTL_RETVAL_COMPLETE) {
                CFISCSI_SESSION_WARN(cs, "ctl_run() failed; error %d; "
                    "dropping connection", error);
                ctl_free_io(io);
                refcount_release(&cs->cs_outstanding_ctl_pdus);
                icl_pdu_free(request);
                cfiscsi_session_terminate(cs);
        }
}

static void
cfiscsi_pdu_handle_task_request(struct icl_pdu *request)
{
        struct iscsi_bhs_task_management_request *bhstmr;
        struct iscsi_bhs_task_management_response *bhstmr2;
        struct icl_pdu *response;
        struct cfiscsi_session *cs;
        union ctl_io *io;
        int error;

        cs = PDU_SESSION(request);
        bhstmr = (struct iscsi_bhs_task_management_request *)request->ip_bhs;
        io = ctl_alloc_io(cs->cs_target->ct_port.ctl_pool_ref);
        ctl_zero_io(io);
        PRIV_REQUEST(io) = request;
        io->io_hdr.io_type = CTL_IO_TASK;
        io->io_hdr.nexus.initid = cs->cs_ctl_initid;
        io->io_hdr.nexus.targ_port = cs->cs_target->ct_port.targ_port;
        io->io_hdr.nexus.targ_lun = ctl_decode_lun(be64toh(bhstmr->bhstmr_lun));
        io->taskio.tag_type = CTL_TAG_SIMPLE; /* XXX */

        switch (bhstmr->bhstmr_function & ~0x80) {
        case BHSTMR_FUNCTION_ABORT_TASK:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_ABORT_TASK");
#endif
                io->taskio.task_action = CTL_TASK_ABORT_TASK;
                io->taskio.tag_num = bhstmr->bhstmr_referenced_task_tag;
                break;
        case BHSTMR_FUNCTION_ABORT_TASK_SET:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_ABORT_TASK_SET");
#endif
                io->taskio.task_action = CTL_TASK_ABORT_TASK_SET;
                break;
        case BHSTMR_FUNCTION_CLEAR_TASK_SET:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_CLEAR_TASK_SET");
#endif
                io->taskio.task_action = CTL_TASK_CLEAR_TASK_SET;
                break;
        case BHSTMR_FUNCTION_LOGICAL_UNIT_RESET:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_LOGICAL_UNIT_RESET");
#endif
                io->taskio.task_action = CTL_TASK_LUN_RESET;
                break;
        case BHSTMR_FUNCTION_TARGET_WARM_RESET:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_TARGET_WARM_RESET");
#endif
                io->taskio.task_action = CTL_TASK_TARGET_RESET;
                break;
        case BHSTMR_FUNCTION_TARGET_COLD_RESET:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_TARGET_COLD_RESET");
#endif
                io->taskio.task_action = CTL_TASK_TARGET_RESET;
                break;
        case BHSTMR_FUNCTION_QUERY_TASK:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_QUERY_TASK");
#endif
                io->taskio.task_action = CTL_TASK_QUERY_TASK;
                io->taskio.tag_num = bhstmr->bhstmr_referenced_task_tag;
                break;
        case BHSTMR_FUNCTION_QUERY_TASK_SET:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_QUERY_TASK_SET");
#endif
                io->taskio.task_action = CTL_TASK_QUERY_TASK_SET;
                break;
        case BHSTMR_FUNCTION_I_T_NEXUS_RESET:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_I_T_NEXUS_RESET");
#endif
                io->taskio.task_action = CTL_TASK_I_T_NEXUS_RESET;
                break;
        case BHSTMR_FUNCTION_QUERY_ASYNC_EVENT:
#if 0
                CFISCSI_SESSION_DEBUG(cs, "BHSTMR_FUNCTION_QUERY_ASYNC_EVENT");
#endif
                io->taskio.task_action = CTL_TASK_QUERY_ASYNC_EVENT;
                break;
        default:
                CFISCSI_SESSION_DEBUG(cs, "unsupported function 0x%x",
                    bhstmr->bhstmr_function & ~0x80);
                ctl_free_io(io);

                response = cfiscsi_pdu_new_response(request, M_NOWAIT);
                if (response == NULL) {
                        CFISCSI_SESSION_WARN(cs, "failed to allocate memory; "
                            "dropping connection");
                        icl_pdu_free(request);
                        cfiscsi_session_terminate(cs);
                        return;
                }
                bhstmr2 = (struct iscsi_bhs_task_management_response *)
                    response->ip_bhs;
                bhstmr2->bhstmr_opcode = ISCSI_BHS_OPCODE_TASK_RESPONSE;
                bhstmr2->bhstmr_flags = 0x80;
                bhstmr2->bhstmr_response =
                    BHSTMR_RESPONSE_FUNCTION_NOT_SUPPORTED;
                bhstmr2->bhstmr_initiator_task_tag =
                    bhstmr->bhstmr_initiator_task_tag;
                icl_pdu_free(request);
                cfiscsi_pdu_queue(response);
                return;
        }

        refcount_acquire(&cs->cs_outstanding_ctl_pdus);
        error = ctl_run(io);
        if (error != CTL_RETVAL_COMPLETE) {
                CFISCSI_SESSION_WARN(cs, "ctl_run() failed; error %d; "
                    "dropping connection", error);
                ctl_free_io(io);
                refcount_release(&cs->cs_outstanding_ctl_pdus);
                icl_pdu_free(request);
                cfiscsi_session_terminate(cs);
        }
}

static bool
cfiscsi_handle_data_segment(struct icl_pdu *request, struct cfiscsi_data_wait *cdw)
{
        struct iscsi_bhs_data_out *bhsdo;
        struct cfiscsi_session *cs;
        struct ctl_sg_entry ctl_sg_entry, *ctl_sglist;
        size_t copy_len, len, off, buffer_offset;
        int ctl_sg_count;
        union ctl_io *io;

        cs = PDU_SESSION(request);

        KASSERT((request->ip_bhs->bhs_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
            ISCSI_BHS_OPCODE_SCSI_DATA_OUT ||
            (request->ip_bhs->bhs_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
            ISCSI_BHS_OPCODE_SCSI_COMMAND,
            ("bad opcode 0x%x", request->ip_bhs->bhs_opcode));

        /*
         * We're only using fields common for Data-Out and SCSI Command PDUs.
         */
        bhsdo = (struct iscsi_bhs_data_out *)request->ip_bhs;

        io = cdw->cdw_ctl_io;
        KASSERT((io->io_hdr.flags & CTL_FLAG_DATA_MASK) != CTL_FLAG_DATA_IN,
            ("CTL_FLAG_DATA_IN"));

#if 0
        CFISCSI_SESSION_DEBUG(cs, "received %zd bytes out of %d",
            request->ip_data_len, io->scsiio.kern_total_len);
#endif

        if (io->scsiio.kern_sg_entries > 0) {
                ctl_sglist = (struct ctl_sg_entry *)io->scsiio.kern_data_ptr;
                ctl_sg_count = io->scsiio.kern_sg_entries;
        } else {
                ctl_sglist = &ctl_sg_entry;
                ctl_sglist->addr = io->scsiio.kern_data_ptr;
                ctl_sglist->len = io->scsiio.kern_data_len;
                ctl_sg_count = 1;
        }

        if ((request->ip_bhs->bhs_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
            ISCSI_BHS_OPCODE_SCSI_DATA_OUT)
                buffer_offset = ntohl(bhsdo->bhsdo_buffer_offset);
        else
                buffer_offset = 0;
        len = icl_pdu_data_segment_length(request);

        /*
         * Make sure the offset, as sent by the initiator, matches the offset
         * we're supposed to be at in the scatter-gather list.
         */
        if (buffer_offset >
            io->scsiio.kern_rel_offset + io->scsiio.ext_data_filled ||
            buffer_offset + len <=
            io->scsiio.kern_rel_offset + io->scsiio.ext_data_filled) {
                CFISCSI_SESSION_WARN(cs, "received bad buffer offset %zd, "
                    "expected %zd; dropping connection", buffer_offset,
                    (size_t)io->scsiio.kern_rel_offset +
                    (size_t)io->scsiio.ext_data_filled);
                ctl_set_data_phase_error(&io->scsiio);
                cfiscsi_session_terminate(cs);
                return (true);
        }

        /*
         * This is the offset within the PDU data segment, as opposed
         * to buffer_offset, which is the offset within the task (SCSI
         * command).
         */
        off = io->scsiio.kern_rel_offset + io->scsiio.ext_data_filled -
            buffer_offset;

        /*
         * Iterate over the scatter/gather segments, filling them with data
         * from the PDU data segment.  Note that this can get called multiple
         * times for one SCSI command; the cdw structure holds state for the
         * scatter/gather list.
         */
        for (;;) {
                KASSERT(cdw->cdw_sg_index < ctl_sg_count,
                    ("cdw->cdw_sg_index >= ctl_sg_count"));
                if (cdw->cdw_sg_len == 0) {
                        cdw->cdw_sg_addr = ctl_sglist[cdw->cdw_sg_index].addr;
                        cdw->cdw_sg_len = ctl_sglist[cdw->cdw_sg_index].len;
                }
                KASSERT(off <= len, ("len > off"));
                copy_len = len - off;
                if (copy_len > cdw->cdw_sg_len)
                        copy_len = cdw->cdw_sg_len;

                icl_pdu_get_data(request, off, cdw->cdw_sg_addr, copy_len);
                cdw->cdw_sg_addr += copy_len;
                cdw->cdw_sg_len -= copy_len;
                off += copy_len;
                io->scsiio.ext_data_filled += copy_len;
                io->scsiio.kern_data_resid -= copy_len;

                if (cdw->cdw_sg_len == 0) {
                        /*
                         * End of current segment.
                         */
                        if (cdw->cdw_sg_index == ctl_sg_count - 1) {
                                /*
                                 * Last segment in scatter/gather list.
                                 */
                                break;
                        }
                        cdw->cdw_sg_index++;
                }

                if (off == len) {
                        /*
                         * End of PDU payload.
                         */
                        break;
                }
        }

        if (len > off) {
                /*
                 * In case of unsolicited data, it's possible that the buffer
                 * provided by CTL is smaller than negotiated FirstBurstLength.
                 * Just ignore the superfluous data; will ask for them with R2T
                 * on next call to cfiscsi_datamove().
                 *
                 * This obviously can only happen with SCSI Command PDU. 
                 */
                if ((request->ip_bhs->bhs_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
                    ISCSI_BHS_OPCODE_SCSI_COMMAND)
                        return (true);

                CFISCSI_SESSION_WARN(cs, "received too much data: got %zd bytes, "
                    "expected %zd; dropping connection",
                    icl_pdu_data_segment_length(request), off);
                ctl_set_data_phase_error(&io->scsiio);
                cfiscsi_session_terminate(cs);
                return (true);
        }

        if (io->scsiio.ext_data_filled == cdw->cdw_r2t_end &&
            (bhsdo->bhsdo_flags & BHSDO_FLAGS_F) == 0) {
                CFISCSI_SESSION_WARN(cs, "got the final packet without "
                    "the F flag; flags = 0x%x; dropping connection",
                    bhsdo->bhsdo_flags);
                ctl_set_data_phase_error(&io->scsiio);
                cfiscsi_session_terminate(cs);
                return (true);
        }

        if (io->scsiio.ext_data_filled != cdw->cdw_r2t_end &&
            (bhsdo->bhsdo_flags & BHSDO_FLAGS_F) != 0) {
                if ((request->ip_bhs->bhs_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
                    ISCSI_BHS_OPCODE_SCSI_DATA_OUT) {
                        CFISCSI_SESSION_WARN(cs, "got the final packet, but the "
                            "transmitted size was %zd bytes instead of %d; "
                            "dropping connection",
                            (size_t)io->scsiio.ext_data_filled,
                            cdw->cdw_r2t_end);
                        ctl_set_data_phase_error(&io->scsiio);
                        cfiscsi_session_terminate(cs);
                        return (true);
                } else {
                        /*
                         * For SCSI Command PDU, this just means we need to
                         * solicit more data by sending R2T.
                         */
                        return (false);
                }
        }

        if (io->scsiio.ext_data_filled == cdw->cdw_r2t_end) {
#if 0
                CFISCSI_SESSION_DEBUG(cs, "no longer expecting Data-Out with target "
                    "transfer tag 0x%x", cdw->cdw_target_transfer_tag);
#endif

                return (true);
        }

        return (false);
}

static void
cfiscsi_pdu_handle_data_out(struct icl_pdu *request)
{
        struct iscsi_bhs_data_out *bhsdo;
        struct cfiscsi_session *cs;
        struct cfiscsi_data_wait *cdw = NULL;
        union ctl_io *io;
        bool done;

        cs = PDU_SESSION(request);
        bhsdo = (struct iscsi_bhs_data_out *)request->ip_bhs;

        CFISCSI_SESSION_LOCK(cs);
        TAILQ_FOREACH(cdw, &cs->cs_waiting_for_data_out, cdw_next) {
#if 0
                CFISCSI_SESSION_DEBUG(cs, "have ttt 0x%x, itt 0x%x; looking for "
                    "ttt 0x%x, itt 0x%x",
                    bhsdo->bhsdo_target_transfer_tag,
                    bhsdo->bhsdo_initiator_task_tag,
                    cdw->cdw_target_transfer_tag, cdw->cdw_initiator_task_tag));
#endif
                if (bhsdo->bhsdo_target_transfer_tag ==
                    cdw->cdw_target_transfer_tag)
                        break;
        }
        CFISCSI_SESSION_UNLOCK(cs);
        if (cdw == NULL) {
                CFISCSI_SESSION_WARN(cs, "data transfer tag 0x%x, initiator task tag "
                    "0x%x, not found; dropping connection",
                    bhsdo->bhsdo_target_transfer_tag, bhsdo->bhsdo_initiator_task_tag);
                icl_pdu_free(request);
                cfiscsi_session_terminate(cs);
                return;
        }

        if (cdw->cdw_datasn != ntohl(bhsdo->bhsdo_datasn)) {
                CFISCSI_SESSION_WARN(cs, "received Data-Out PDU with "
                    "DataSN %u, while expected %u; dropping connection",
                    ntohl(bhsdo->bhsdo_datasn), cdw->cdw_datasn);
                icl_pdu_free(request);
                cfiscsi_session_terminate(cs);
                return;
        }
        cdw->cdw_datasn += request->ip_additional_pdus + 1;

        io = cdw->cdw_ctl_io;
        KASSERT((io->io_hdr.flags & CTL_FLAG_DATA_MASK) != CTL_FLAG_DATA_IN,
            ("CTL_FLAG_DATA_IN"));

        done = cfiscsi_handle_data_segment(request, cdw);
        if (done) {
                CFISCSI_SESSION_LOCK(cs);
                TAILQ_REMOVE(&cs->cs_waiting_for_data_out, cdw, cdw_next);
                CFISCSI_SESSION_UNLOCK(cs);
                done = (io->scsiio.ext_data_filled != cdw->cdw_r2t_end ||
                    io->scsiio.ext_data_filled == io->scsiio.kern_data_len);
                cfiscsi_data_wait_free(cs, cdw);
                io->io_hdr.flags &= ~CTL_FLAG_DMA_INPROG;
                if (done)
                        ctl_datamove_done(io, false);
                else
                        cfiscsi_datamove_out(io);
        }

        icl_pdu_free(request);
}

static void
cfiscsi_pdu_handle_logout_request(struct icl_pdu *request)
{
        struct iscsi_bhs_logout_request *bhslr;
        struct iscsi_bhs_logout_response *bhslr2;
        struct icl_pdu *response;
        struct cfiscsi_session *cs;

        cs = PDU_SESSION(request);
        bhslr = (struct iscsi_bhs_logout_request *)request->ip_bhs;
        switch (bhslr->bhslr_reason & 0x7f) {
        case BHSLR_REASON_CLOSE_SESSION:
        case BHSLR_REASON_CLOSE_CONNECTION:
                response = cfiscsi_pdu_new_response(request, M_NOWAIT);
                if (response == NULL) {
                        CFISCSI_SESSION_DEBUG(cs, "failed to allocate memory");
                        icl_pdu_free(request);
                        cfiscsi_session_terminate(cs);
                        return;
                }
                bhslr2 = (struct iscsi_bhs_logout_response *)response->ip_bhs;
                bhslr2->bhslr_opcode = ISCSI_BHS_OPCODE_LOGOUT_RESPONSE;
                bhslr2->bhslr_flags = 0x80;
                bhslr2->bhslr_response = BHSLR_RESPONSE_CLOSED_SUCCESSFULLY;
                bhslr2->bhslr_initiator_task_tag =
                    bhslr->bhslr_initiator_task_tag;
                icl_pdu_free(request);
                cfiscsi_pdu_queue(response);
                cfiscsi_session_terminate(cs);
                break;
        case BHSLR_REASON_REMOVE_FOR_RECOVERY:
                response = cfiscsi_pdu_new_response(request, M_NOWAIT);
                if (response == NULL) {
                        CFISCSI_SESSION_WARN(cs,
                            "failed to allocate memory; dropping connection");
                        icl_pdu_free(request);
                        cfiscsi_session_terminate(cs);
                        return;
                }
                bhslr2 = (struct iscsi_bhs_logout_response *)response->ip_bhs;
                bhslr2->bhslr_opcode = ISCSI_BHS_OPCODE_LOGOUT_RESPONSE;
                bhslr2->bhslr_flags = 0x80;
                bhslr2->bhslr_response = BHSLR_RESPONSE_RECOVERY_NOT_SUPPORTED;
                bhslr2->bhslr_initiator_task_tag =
                    bhslr->bhslr_initiator_task_tag;
                icl_pdu_free(request);
                cfiscsi_pdu_queue(response);
                break;
        default:
                CFISCSI_SESSION_WARN(cs, "invalid reason 0%x; dropping connection",
                    bhslr->bhslr_reason);
                icl_pdu_free(request);
                cfiscsi_session_terminate(cs);
                break;
        }
}

static void
cfiscsi_callout(void *context)
{
        struct icl_pdu *cp;
        struct iscsi_bhs_nop_in *bhsni;
        struct cfiscsi_session *cs;

        cs = context;

        if (cs->cs_terminating) 
                return;

        callout_schedule(&cs->cs_callout, 1 * hz);

        atomic_add_int(&cs->cs_timeout, 1);

#ifdef ICL_KERNEL_PROXY
        if (cs->cs_waiting_for_ctld || cs->cs_login_phase) {
                if (login_timeout > 0 && cs->cs_timeout > login_timeout) {
                        CFISCSI_SESSION_WARN(cs, "login timed out after "
                            "%d seconds; dropping connection", cs->cs_timeout);
                        cfiscsi_session_terminate(cs);
                }
                return;
        }
#endif

        if (ping_timeout <= 0) {
                /*
                 * Pings are disabled.  Don't send NOP-In in this case;
                 * user might have disabled pings to work around problems
                 * with certain initiators that can't properly handle
                 * NOP-In, such as iPXE.  Reset the timeout, to avoid
                 * triggering reconnection, should the user decide to
                 * reenable them.
                 */
                cs->cs_timeout = 0;
                return;
        }

        if (cs->cs_timeout >= ping_timeout) {
                CFISCSI_SESSION_WARN(cs, "no ping reply (NOP-Out) after %d seconds; "
                    "dropping connection",  ping_timeout);
                cfiscsi_session_terminate(cs);
                return;
        }

        /*
         * If the ping was reset less than one second ago - which means
         * that we've received some PDU during the last second - assume
         * the traffic flows correctly and don't bother sending a NOP-Out.
         *
         * (It's 2 - one for one second, and one for incrementing is_timeout
         * earlier in this routine.)
         */
        if (cs->cs_timeout < 2)
                return;

        cp = icl_pdu_new(cs->cs_conn, M_NOWAIT);
        if (cp == NULL) {
                CFISCSI_SESSION_WARN(cs, "failed to allocate memory");
                return;
        }
        bhsni = (struct iscsi_bhs_nop_in *)cp->ip_bhs;
        bhsni->bhsni_opcode = ISCSI_BHS_OPCODE_NOP_IN;
        bhsni->bhsni_flags = 0x80;
        bhsni->bhsni_initiator_task_tag = 0xffffffff;

        cfiscsi_pdu_queue(cp);
}

static struct cfiscsi_data_wait *
cfiscsi_data_wait_new(struct cfiscsi_session *cs, union ctl_io *io,
    uint32_t initiator_task_tag, uint32_t *target_transfer_tagp)
{
        struct cfiscsi_data_wait *cdw;
        int error;

        cdw = uma_zalloc(cfiscsi_data_wait_zone, M_NOWAIT | M_ZERO);
        if (cdw == NULL) {
                CFISCSI_SESSION_WARN(cs,
                    "failed to allocate %zd bytes", sizeof(*cdw));
                return (NULL);
        }

        error = icl_conn_transfer_setup(cs->cs_conn, PRIV_REQUEST(io), io,
            target_transfer_tagp, &cdw->cdw_icl_prv);
        if (error != 0) {
                CFISCSI_SESSION_WARN(cs,
                    "icl_conn_transfer_setup() failed with error %d", error);
                uma_zfree(cfiscsi_data_wait_zone, cdw);
                return (NULL);
        }

        cdw->cdw_ctl_io = io;
        cdw->cdw_target_transfer_tag = *target_transfer_tagp;
        cdw->cdw_initiator_task_tag = initiator_task_tag;

        return (cdw);
}

static void
cfiscsi_data_wait_free(struct cfiscsi_session *cs,
    struct cfiscsi_data_wait *cdw)
{

        icl_conn_transfer_done(cs->cs_conn, cdw->cdw_icl_prv);
        uma_zfree(cfiscsi_data_wait_zone, cdw);
}

static void
cfiscsi_data_wait_abort(struct cfiscsi_session *cs,
    struct cfiscsi_data_wait *cdw, int status)
{
        union ctl_io *cdw_io;

        /*
         * Set nonzero port status; this prevents backends from
         * assuming that the data transfer actually succeeded
         * and writing uninitialized data to disk.
         */
        MPASS(status != 0);
        cdw_io = cdw->cdw_ctl_io;
        cdw_io->io_hdr.flags &= ~CTL_FLAG_DMA_INPROG;
        cdw_io->scsiio.io_hdr.port_status = status;
        cfiscsi_data_wait_free(cs, cdw);
        ctl_datamove_done(cdw_io, false);
}

static void
cfiscsi_session_terminate_tasks(struct cfiscsi_session *cs)
{
        struct cfiscsi_data_wait *cdw;
        struct icl_pdu *ip;
        union ctl_io *io;
        int error, last, wait;

        if (cs->cs_target == NULL)
                return;         /* No target yet, so nothing to do. */
        ip = icl_pdu_new(cs->cs_conn, M_WAITOK);
        ip->ip_bhs->bhs_opcode = ISCSI_BHS_OPCODE_INTERNAL;
        io = ctl_alloc_io(cs->cs_target->ct_port.ctl_pool_ref);
        ctl_zero_io(io);
        PRIV_REQUEST(io) = ip;
        io->io_hdr.io_type = CTL_IO_TASK;
        io->io_hdr.nexus.initid = cs->cs_ctl_initid;
        io->io_hdr.nexus.targ_port = cs->cs_target->ct_port.targ_port;
        io->io_hdr.nexus.targ_lun = 0;
        io->taskio.tag_type = CTL_TAG_SIMPLE; /* XXX */
        io->taskio.task_action = CTL_TASK_I_T_NEXUS_RESET;
        wait = cs->cs_outstanding_ctl_pdus;
        refcount_acquire(&cs->cs_outstanding_ctl_pdus);
        error = ctl_run(io);
        if (error != CTL_RETVAL_COMPLETE) {
                CFISCSI_SESSION_WARN(cs, "ctl_run() failed; error %d", error);
                refcount_release(&cs->cs_outstanding_ctl_pdus);
                ctl_free_io(io);
                icl_pdu_free(ip);
        }

        CFISCSI_SESSION_LOCK(cs);
        cs->cs_terminating_tasks = true;
        while ((cdw = TAILQ_FIRST(&cs->cs_waiting_for_data_out)) != NULL) {
                TAILQ_REMOVE(&cs->cs_waiting_for_data_out, cdw, cdw_next);
                CFISCSI_SESSION_UNLOCK(cs);
                cfiscsi_data_wait_abort(cs, cdw, 42);
                CFISCSI_SESSION_LOCK(cs);
        }
        CFISCSI_SESSION_UNLOCK(cs);

        /*
         * Wait for CTL to terminate all the tasks.
         */
        if (wait > 0)
                CFISCSI_SESSION_WARN(cs,
                    "waiting for CTL to terminate %d tasks", wait);
        for (;;) {
                refcount_acquire(&cs->cs_outstanding_ctl_pdus);
                last = refcount_release(&cs->cs_outstanding_ctl_pdus);
                if (last != 0)
                        break;
                tsleep(__DEVOLATILE(void *, &cs->cs_outstanding_ctl_pdus),
                    0, "cfiscsi_terminate", hz / 100);
        }
        if (wait > 0)
                CFISCSI_SESSION_WARN(cs, "tasks terminated");
}

static void
cfiscsi_maintenance_thread(void *arg)
{
        struct cfiscsi_session *cs;

        cs = arg;

        for (;;) {
                CFISCSI_SESSION_LOCK(cs);
                if (cs->cs_terminating == false || cs->cs_handoff_in_progress)
                        cv_wait(&cs->cs_maintenance_cv, &cs->cs_lock);
                CFISCSI_SESSION_UNLOCK(cs);

                if (cs->cs_terminating && cs->cs_handoff_in_progress == false) {
                        /*
                         * We used to wait up to 30 seconds to deliver queued
                         * PDUs to the initiator.  We also tried hard to deliver
                         * SCSI Responses for the aborted PDUs.  We don't do
                         * that anymore.  We might need to revisit that.
                         */
                        callout_drain(&cs->cs_callout);
                        icl_conn_close(cs->cs_conn);

                        /*
                         * At this point ICL receive thread is no longer
                         * running; no new tasks can be queued.
                         */
                        cfiscsi_session_terminate_tasks(cs);
                        cfiscsi_session_delete(cs);
                        kthread_exit();
                        return;
                }
                CFISCSI_SESSION_DEBUG(cs, "nothing to do");
        }
}

static void
cfiscsi_session_terminate(struct cfiscsi_session *cs)
{

        cs->cs_terminating = true;
        cv_signal(&cs->cs_maintenance_cv);
#ifdef ICL_KERNEL_PROXY
        cv_signal(&cs->cs_login_cv);
#endif
}

static int
cfiscsi_session_register_initiator(struct cfiscsi_session *cs)
{
        struct cfiscsi_target *ct;
        char *name;
        int i;

        KASSERT(cs->cs_ctl_initid == -1, ("already registered"));

        ct = cs->cs_target;
        name = strdup(cs->cs_initiator_id, M_CTL);
        i = ctl_add_initiator(&ct->ct_port, -1, 0, name);
        if (i < 0) {
                CFISCSI_SESSION_WARN(cs, "ctl_add_initiator failed with error %d",
                    i);
                cs->cs_ctl_initid = -1;
                return (1);
        }
        cs->cs_ctl_initid = i;
#if 0
        CFISCSI_SESSION_DEBUG(cs, "added initiator id %d", i);
#endif

        return (0);
}

static void
cfiscsi_session_unregister_initiator(struct cfiscsi_session *cs)
{
        int error;

        if (cs->cs_ctl_initid == -1)
                return;

        error = ctl_remove_initiator(&cs->cs_target->ct_port, cs->cs_ctl_initid);
        if (error != 0) {
                CFISCSI_SESSION_WARN(cs, "ctl_remove_initiator failed with error %d",
                    error);
        }
        cs->cs_ctl_initid = -1;
}

static struct cfiscsi_session *
cfiscsi_session_new(struct cfiscsi_softc *softc, const char *offload)
{
        struct cfiscsi_session *cs;
        int error;

        cs = malloc(sizeof(*cs), M_CFISCSI, M_NOWAIT | M_ZERO);
        if (cs == NULL) {
                CFISCSI_WARN("malloc failed");
                return (NULL);
        }
        cs->cs_ctl_initid = -1;

        refcount_init(&cs->cs_outstanding_ctl_pdus, 0);
        TAILQ_INIT(&cs->cs_waiting_for_data_out);
        mtx_init(&cs->cs_lock, "cfiscsi_lock", NULL, MTX_DEF);
        cv_init(&cs->cs_maintenance_cv, "cfiscsi_mt");
#ifdef ICL_KERNEL_PROXY
        cv_init(&cs->cs_login_cv, "cfiscsi_login");
#endif

        /*
         * The purpose of this is to avoid racing with session shutdown.
         * Otherwise we could have the maintenance thread call icl_conn_close()
         * before we call icl_conn_handoff().
         */
        cs->cs_handoff_in_progress = true;

        cs->cs_conn = icl_new_conn(offload, false, "cfiscsi", &cs->cs_lock);
        if (cs->cs_conn == NULL) {
                free(cs, M_CFISCSI);
                return (NULL);
        }
        cs->cs_conn->ic_receive = cfiscsi_receive_callback;
        cs->cs_conn->ic_error = cfiscsi_error_callback;
        cs->cs_conn->ic_prv0 = cs;

        error = kthread_add(cfiscsi_maintenance_thread, cs, NULL, NULL, 0, 0, "cfiscsimt");
        if (error != 0) {
                CFISCSI_SESSION_WARN(cs, "kthread_add(9) failed with error %d", error);
                free(cs, M_CFISCSI);
                return (NULL);
        }

        mtx_lock(&softc->lock);
        cs->cs_id = ++softc->last_session_id;
        TAILQ_INSERT_TAIL(&softc->sessions, cs, cs_next);
        mtx_unlock(&softc->lock);

        /*
         * Start pinging the initiator.
         */
        callout_init(&cs->cs_callout, 1);
        callout_reset(&cs->cs_callout, 1 * hz, cfiscsi_callout, cs);

        return (cs);
}

static void
cfiscsi_session_delete(struct cfiscsi_session *cs)
{
        struct cfiscsi_softc *softc;

        softc = &cfiscsi_softc;

        KASSERT(cs->cs_outstanding_ctl_pdus == 0,
            ("destroying session with outstanding CTL pdus"));
        KASSERT(TAILQ_EMPTY(&cs->cs_waiting_for_data_out),
            ("destroying session with non-empty queue"));

        mtx_lock(&softc->lock);
        TAILQ_REMOVE(&softc->sessions, cs, cs_next);
        mtx_unlock(&softc->lock);

        cfiscsi_session_unregister_initiator(cs);
        if (cs->cs_target != NULL)
                cfiscsi_target_release(cs->cs_target);
        icl_conn_close(cs->cs_conn);
        icl_conn_free(cs->cs_conn);
        free(cs, M_CFISCSI);
        cv_signal(&softc->sessions_cv);
}

static int
cfiscsi_init(void)
{
        struct cfiscsi_softc *softc;

        softc = &cfiscsi_softc;
        bzero(softc, sizeof(*softc));
        mtx_init(&softc->lock, "cfiscsi", NULL, MTX_DEF);

        cv_init(&softc->sessions_cv, "cfiscsi_sessions");
#ifdef ICL_KERNEL_PROXY
        cv_init(&softc->accept_cv, "cfiscsi_accept");
#endif
        TAILQ_INIT(&softc->sessions);
        TAILQ_INIT(&softc->targets);

        cfiscsi_data_wait_zone = uma_zcreate("cfiscsi_data_wait",
            sizeof(struct cfiscsi_data_wait), NULL, NULL, NULL, NULL,
            UMA_ALIGN_PTR, 0);

        return (0);
}

static int
cfiscsi_shutdown(void)
{
        struct cfiscsi_softc *softc = &cfiscsi_softc;

        if (!TAILQ_EMPTY(&softc->sessions) || !TAILQ_EMPTY(&softc->targets))
                return (EBUSY);

        uma_zdestroy(cfiscsi_data_wait_zone);
#ifdef ICL_KERNEL_PROXY
        cv_destroy(&softc->accept_cv);
#endif
        cv_destroy(&softc->sessions_cv);
        mtx_destroy(&softc->lock);
        return (0);
}

#ifdef ICL_KERNEL_PROXY
static void
cfiscsi_accept(struct socket *so, struct sockaddr *sa, int portal_id)
{
        struct cfiscsi_session *cs;

        cs = cfiscsi_session_new(&cfiscsi_softc, NULL);
        if (cs == NULL) {
                CFISCSI_WARN("failed to create session");
                return;
        }

        icl_conn_handoff_sock(cs->cs_conn, so);
        cs->cs_initiator_sa = sa;
        cs->cs_portal_id = portal_id;
        cs->cs_handoff_in_progress = false;
        cs->cs_waiting_for_ctld = true;
        cv_signal(&cfiscsi_softc.accept_cv);

        CFISCSI_SESSION_LOCK(cs);
        /*
         * Wake up the maintenance thread if we got scheduled for termination
         * somewhere between cfiscsi_session_new() and icl_conn_handoff_sock().
         */
        if (cs->cs_terminating)
                cfiscsi_session_terminate(cs);
        CFISCSI_SESSION_UNLOCK(cs);
}
#endif

static void
cfiscsi_online(void *arg)
{
        struct cfiscsi_softc *softc;
        struct cfiscsi_target *ct;
        int online;

        ct = (struct cfiscsi_target *)arg;
        softc = ct->ct_softc;

        mtx_lock(&softc->lock);
        if (ct->ct_online) {
                mtx_unlock(&softc->lock);
                return;
        }
        ct->ct_online = 1;
        online = softc->online++;
        mtx_unlock(&softc->lock);
        if (online > 0)
                return;

#ifdef ICL_KERNEL_PROXY
        if (softc->listener != NULL)
                icl_listen_free(softc->listener);
        softc->listener = icl_listen_new(cfiscsi_accept);
#endif
}

static void
cfiscsi_offline(void *arg)
{
        struct cfiscsi_softc *softc;
        struct cfiscsi_target *ct;
        struct cfiscsi_session *cs;
        int error, online;

        ct = (struct cfiscsi_target *)arg;
        softc = ct->ct_softc;

        mtx_lock(&softc->lock);
        if (!ct->ct_online) {
                mtx_unlock(&softc->lock);
                return;
        }
        ct->ct_online = 0;
        online = --softc->online;

        do {
                TAILQ_FOREACH(cs, &softc->sessions, cs_next) {
                        if (cs->cs_target == ct)
                                cfiscsi_session_terminate(cs);
                }
                TAILQ_FOREACH(cs, &softc->sessions, cs_next) {
                        if (cs->cs_target == ct)
                                break;
                }
                if (cs != NULL) {
                        error = cv_wait_sig(&softc->sessions_cv, &softc->lock);
                        if (error != 0) {
                                CFISCSI_SESSION_DEBUG(cs,
                                    "cv_wait failed with error %d\n", error);
                                break;
                        }
                }
        } while (cs != NULL && ct->ct_online == 0);
        mtx_unlock(&softc->lock);
        if (online > 0)
                return;

#ifdef ICL_KERNEL_PROXY
        icl_listen_free(softc->listener);
        softc->listener = NULL;
#endif
}

static int
cfiscsi_info(void *arg, struct sbuf *sb)
{
        struct cfiscsi_target *ct = (struct cfiscsi_target *)arg;
        int retval;

        retval = sbuf_printf(sb, "\t<cfiscsi_state>%d</cfiscsi_state>\n",
            ct->ct_state);
        return (retval);
}

static void
cfiscsi_ioctl_handoff(struct ctl_iscsi *ci)
{
        struct cfiscsi_softc *softc;
        struct cfiscsi_session *cs, *cs2;
        struct cfiscsi_target *ct;
        struct ctl_iscsi_handoff_params *cihp;
        int error;

        cihp = (struct ctl_iscsi_handoff_params *)&(ci->data);
        softc = &cfiscsi_softc;

        CFISCSI_DEBUG("new connection from %s (%s) to %s",
            cihp->initiator_name, cihp->initiator_addr,
            cihp->target_name);

        ct = cfiscsi_target_find(softc, cihp->target_name,
            cihp->portal_group_tag);
        if (ct == NULL) {
                ci->status = CTL_ISCSI_ERROR;
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "%s: target not found", __func__);
                return;
        }

#ifdef ICL_KERNEL_PROXY
        if (cihp->socket > 0 && cihp->connection_id > 0) {
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "both socket and connection_id set");
                ci->status = CTL_ISCSI_ERROR;
                cfiscsi_target_release(ct);
                return;
        }
        if (cihp->socket == 0) {
                mtx_lock(&cfiscsi_softc.lock);
                TAILQ_FOREACH(cs, &cfiscsi_softc.sessions, cs_next) {
                        if (cs->cs_id == cihp->connection_id)
                                break;
                }
                if (cs == NULL) {
                        mtx_unlock(&cfiscsi_softc.lock);
                        snprintf(ci->error_str, sizeof(ci->error_str),
                            "connection not found");
                        ci->status = CTL_ISCSI_ERROR;
                        cfiscsi_target_release(ct);
                        return;
                }
                mtx_unlock(&cfiscsi_softc.lock);
        } else {
#endif
                cs = cfiscsi_session_new(softc, cihp->offload);
                if (cs == NULL) {
                        ci->status = CTL_ISCSI_ERROR;
                        snprintf(ci->error_str, sizeof(ci->error_str),
                            "%s: cfiscsi_session_new failed", __func__);
                        cfiscsi_target_release(ct);
                        return;
                }
#ifdef ICL_KERNEL_PROXY
        }
#endif

        /*
         * First PDU of Full Feature phase has the same CmdSN as the last
         * PDU from the Login Phase received from the initiator.  Thus,
         * the -1 below.
         */
        cs->cs_cmdsn = cihp->cmdsn;
        cs->cs_statsn = cihp->statsn;
        cs->cs_conn->ic_max_recv_data_segment_length =
            cihp->max_recv_data_segment_length;
        cs->cs_conn->ic_max_send_data_segment_length =
            cihp->max_send_data_segment_length;
        cs->cs_max_burst_length = cihp->max_burst_length;
        cs->cs_first_burst_length = cihp->first_burst_length;
        cs->cs_immediate_data = !!cihp->immediate_data;
        if (cihp->header_digest == CTL_ISCSI_DIGEST_CRC32C)
                cs->cs_conn->ic_header_crc32c = true;
        if (cihp->data_digest == CTL_ISCSI_DIGEST_CRC32C)
                cs->cs_conn->ic_data_crc32c = true;

        strlcpy(cs->cs_initiator_name,
            cihp->initiator_name, sizeof(cs->cs_initiator_name));
        strlcpy(cs->cs_initiator_addr,
            cihp->initiator_addr, sizeof(cs->cs_initiator_addr));
        strlcpy(cs->cs_initiator_alias,
            cihp->initiator_alias, sizeof(cs->cs_initiator_alias));
        memcpy(cs->cs_initiator_isid,
            cihp->initiator_isid, sizeof(cs->cs_initiator_isid));
        snprintf(cs->cs_initiator_id, sizeof(cs->cs_initiator_id),
            "%s,i,0x%02x%02x%02x%02x%02x%02x", cs->cs_initiator_name,
            cihp->initiator_isid[0], cihp->initiator_isid[1],
            cihp->initiator_isid[2], cihp->initiator_isid[3],
            cihp->initiator_isid[4], cihp->initiator_isid[5]);

        mtx_lock(&softc->lock);
        if (ct->ct_online == 0) {
                mtx_unlock(&softc->lock);
                CFISCSI_SESSION_LOCK(cs);
                cs->cs_handoff_in_progress = false;
                cfiscsi_session_terminate(cs);
                CFISCSI_SESSION_UNLOCK(cs);
                cfiscsi_target_release(ct);
                ci->status = CTL_ISCSI_ERROR;
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "%s: port offline", __func__);
                return;
        }
        cs->cs_target = ct;
        mtx_unlock(&softc->lock);

restart:
        if (!cs->cs_terminating) {
                mtx_lock(&softc->lock);
                TAILQ_FOREACH(cs2, &softc->sessions, cs_next) {
                        if (cs2 != cs && cs2->cs_tasks_aborted == false &&
                            cs->cs_target == cs2->cs_target &&
                            strcmp(cs->cs_initiator_id, cs2->cs_initiator_id) == 0) {
                                if (strcmp(cs->cs_initiator_addr,
                                    cs2->cs_initiator_addr) != 0) {
                                        CFISCSI_SESSION_WARN(cs2,
                                            "session reinstatement from "
                                            "different address %s",
                                            cs->cs_initiator_addr);
                                } else {
                                        CFISCSI_SESSION_DEBUG(cs2,
                                            "session reinstatement");
                                }
                                cfiscsi_session_terminate(cs2);
                                mtx_unlock(&softc->lock);
                                pause("cfiscsi_reinstate", 1);
                                goto restart;
                        }
                }
                mtx_unlock(&softc->lock);
        }

        /*
         * Register initiator with CTL.
         */
        cfiscsi_session_register_initiator(cs);

#ifdef ICL_KERNEL_PROXY
        if (cihp->socket > 0) {
#endif
                error = icl_conn_handoff(cs->cs_conn, cihp->socket);
                if (error != 0) {
                        CFISCSI_SESSION_LOCK(cs);
                        cs->cs_handoff_in_progress = false;
                        cfiscsi_session_terminate(cs);
                        CFISCSI_SESSION_UNLOCK(cs);
                        ci->status = CTL_ISCSI_ERROR;
                        snprintf(ci->error_str, sizeof(ci->error_str),
                            "%s: icl_conn_handoff failed with error %d",
                            __func__, error);
                        return;
                }
#ifdef ICL_KERNEL_PROXY
        }
#endif

#ifdef ICL_KERNEL_PROXY
        cs->cs_login_phase = false;

        /*
         * First PDU of the Full Feature phase has likely already arrived.
         * We have to pick it up and execute properly.
         */
        if (cs->cs_login_pdu != NULL) {
                CFISCSI_SESSION_DEBUG(cs, "picking up first PDU");
                cfiscsi_pdu_handle(cs->cs_login_pdu);
                cs->cs_login_pdu = NULL;
        }
#endif

        CFISCSI_SESSION_LOCK(cs);
        cs->cs_handoff_in_progress = false;

        /*
         * Wake up the maintenance thread if we got scheduled for termination.
         */
        if (cs->cs_terminating)
                cfiscsi_session_terminate(cs);
        CFISCSI_SESSION_UNLOCK(cs);

        ci->status = CTL_ISCSI_OK;
}

static void
cfiscsi_ioctl_list(struct ctl_iscsi *ci)
{
        struct ctl_iscsi_list_params *cilp;
        struct cfiscsi_session *cs;
        struct cfiscsi_softc *softc;
        struct sbuf *sb;
        int error;

        cilp = (struct ctl_iscsi_list_params *)&(ci->data);
        softc = &cfiscsi_softc;

        sb = sbuf_new(NULL, NULL, cilp->alloc_len, SBUF_FIXEDLEN);
        if (sb == NULL) {
                ci->status = CTL_ISCSI_ERROR;
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "Unable to allocate %d bytes for iSCSI session list",
                    cilp->alloc_len);
                return;
        }

        sbuf_cat(sb, "<ctlislist>\n");
        mtx_lock(&softc->lock);
        TAILQ_FOREACH(cs, &softc->sessions, cs_next) {
                if (cs->cs_target == NULL)
                        continue;
                error = sbuf_printf(sb, "<connection id=\"%d\">"
                    "<initiator>%s</initiator>"
                    "<initiator_addr>%s</initiator_addr>"
                    "<initiator_alias>%s</initiator_alias>"
                    "<target>%s</target>"
                    "<target_alias>%s</target_alias>"
                    "<target_portal_group_tag>%u</target_portal_group_tag>"
                    "<header_digest>%s</header_digest>"
                    "<data_digest>%s</data_digest>"
                    "<max_recv_data_segment_length>%d</max_recv_data_segment_length>"
                    "<max_send_data_segment_length>%d</max_send_data_segment_length>"
                    "<max_burst_length>%d</max_burst_length>"
                    "<first_burst_length>%d</first_burst_length>"
                    "<immediate_data>%d</immediate_data>"
                    "<iser>%d</iser>"
                    "<offload>%s</offload>"
                    "</connection>\n",
                    cs->cs_id,
                    cs->cs_initiator_name, cs->cs_initiator_addr, cs->cs_initiator_alias,
                    cs->cs_target->ct_name, cs->cs_target->ct_alias,
                    cs->cs_target->ct_tag,
                    cs->cs_conn->ic_header_crc32c ? "CRC32C" : "None",
                    cs->cs_conn->ic_data_crc32c ? "CRC32C" : "None",
                    cs->cs_conn->ic_max_recv_data_segment_length,
                    cs->cs_conn->ic_max_send_data_segment_length,
                    cs->cs_max_burst_length,
                    cs->cs_first_burst_length,
                    cs->cs_immediate_data,
                    cs->cs_conn->ic_iser,
                    cs->cs_conn->ic_offload);
                if (error != 0)
                        break;
        }
        mtx_unlock(&softc->lock);
        error = sbuf_cat(sb, "</ctlislist>\n");
        if (error != 0) {
                sbuf_delete(sb);
                ci->status = CTL_ISCSI_LIST_NEED_MORE_SPACE;
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "Out of space, %d bytes is too small", cilp->alloc_len);
                return;
        }
        sbuf_finish(sb);

        error = copyout(sbuf_data(sb), cilp->conn_xml, sbuf_len(sb) + 1);
        if (error != 0) {
                sbuf_delete(sb);
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "copyout failed with error %d", error);
                ci->status = CTL_ISCSI_ERROR;
                return;
        }
        cilp->fill_len = sbuf_len(sb) + 1;
        ci->status = CTL_ISCSI_OK;
        sbuf_delete(sb);
}

static void
cfiscsi_ioctl_logout(struct ctl_iscsi *ci)
{
        struct icl_pdu *response;
        struct iscsi_bhs_asynchronous_message *bhsam;
        struct ctl_iscsi_logout_params *cilp;
        struct cfiscsi_session *cs;
        struct cfiscsi_softc *softc;
        int found = 0;

        cilp = (struct ctl_iscsi_logout_params *)&(ci->data);
        softc = &cfiscsi_softc;

        mtx_lock(&softc->lock);
        TAILQ_FOREACH(cs, &softc->sessions, cs_next) {
                if (cilp->all == 0 && cs->cs_id != cilp->connection_id &&
                    strcmp(cs->cs_initiator_name, cilp->initiator_name) != 0 &&
                    strcmp(cs->cs_initiator_addr, cilp->initiator_addr) != 0)
                        continue;

                response = icl_pdu_new(cs->cs_conn, M_NOWAIT);
                if (response == NULL) {
                        ci->status = CTL_ISCSI_ERROR;
                        snprintf(ci->error_str, sizeof(ci->error_str),
                            "Unable to allocate memory");
                        mtx_unlock(&softc->lock);
                        return;
                }
                bhsam =
                    (struct iscsi_bhs_asynchronous_message *)response->ip_bhs;
                bhsam->bhsam_opcode = ISCSI_BHS_OPCODE_ASYNC_MESSAGE;
                bhsam->bhsam_flags = 0x80;
                bhsam->bhsam_async_event = BHSAM_EVENT_TARGET_REQUESTS_LOGOUT;
                bhsam->bhsam_parameter3 = htons(10);
                cfiscsi_pdu_queue(response);
                found++;
        }
        mtx_unlock(&softc->lock);

        if (found == 0) {
                ci->status = CTL_ISCSI_SESSION_NOT_FOUND;
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "No matching connections found");
                return;
        }

        ci->status = CTL_ISCSI_OK;
}

static void
cfiscsi_ioctl_terminate(struct ctl_iscsi *ci)
{
        struct icl_pdu *response;
        struct iscsi_bhs_asynchronous_message *bhsam;
        struct ctl_iscsi_terminate_params *citp;
        struct cfiscsi_session *cs;
        struct cfiscsi_softc *softc;
        int found = 0;

        citp = (struct ctl_iscsi_terminate_params *)&(ci->data);
        softc = &cfiscsi_softc;

        mtx_lock(&softc->lock);
        TAILQ_FOREACH(cs, &softc->sessions, cs_next) {
                if (citp->all == 0 && cs->cs_id != citp->connection_id &&
                    strcmp(cs->cs_initiator_name, citp->initiator_name) != 0 &&
                    strcmp(cs->cs_initiator_addr, citp->initiator_addr) != 0)
                        continue;

                response = icl_pdu_new(cs->cs_conn, M_NOWAIT);
                if (response == NULL) {
                        /*
                         * Oh well.  Just terminate the connection.
                         */
                } else {
                        bhsam = (struct iscsi_bhs_asynchronous_message *)
                            response->ip_bhs;
                        bhsam->bhsam_opcode = ISCSI_BHS_OPCODE_ASYNC_MESSAGE;
                        bhsam->bhsam_flags = 0x80;
                        bhsam->bhsam_0xffffffff = 0xffffffff;
                        bhsam->bhsam_async_event =
                            BHSAM_EVENT_TARGET_TERMINATES_SESSION;
                        cfiscsi_pdu_queue(response);
                }
                cfiscsi_session_terminate(cs);
                found++;
        }
        mtx_unlock(&softc->lock);

        if (found == 0) {
                ci->status = CTL_ISCSI_SESSION_NOT_FOUND;
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "No matching connections found");
                return;
        }

        ci->status = CTL_ISCSI_OK;
}

static void
cfiscsi_ioctl_limits(struct ctl_iscsi *ci)
{
        struct ctl_iscsi_limits_params *cilp;
        struct icl_drv_limits idl;
        int error;

        cilp = (struct ctl_iscsi_limits_params *)&(ci->data);

        error = icl_limits(cilp->offload, false, cilp->socket, &idl);
        if (error != 0) {
                ci->status = CTL_ISCSI_ERROR;
                snprintf(ci->error_str, sizeof(ci->error_str),
                        "%s: icl_limits failed with error %d",
                        __func__, error);
                return;
        }

        cilp->max_recv_data_segment_length =
            idl.idl_max_recv_data_segment_length;
        cilp->max_send_data_segment_length =
            idl.idl_max_send_data_segment_length;
        cilp->max_burst_length = idl.idl_max_burst_length;
        cilp->first_burst_length = idl.idl_first_burst_length;

        ci->status = CTL_ISCSI_OK;
}

#ifdef ICL_KERNEL_PROXY
static void
cfiscsi_ioctl_listen(struct ctl_iscsi *ci)
{
        struct ctl_iscsi_listen_params *cilp;
        struct sockaddr *sa;
        int error;

        cilp = (struct ctl_iscsi_listen_params *)&(ci->data);

        if (cfiscsi_softc.listener == NULL) {
                CFISCSI_DEBUG("no listener");
                snprintf(ci->error_str, sizeof(ci->error_str), "no listener");
                ci->status = CTL_ISCSI_ERROR;
                return;
        }

        error = getsockaddr(&sa, (void *)cilp->addr, cilp->addrlen);
        if (error != 0) {
                CFISCSI_DEBUG("getsockaddr, error %d", error);
                snprintf(ci->error_str, sizeof(ci->error_str), "getsockaddr failed");
                ci->status = CTL_ISCSI_ERROR;
                return;
        }

        error = icl_listen_add(cfiscsi_softc.listener, cilp->iser, cilp->domain,
            cilp->socktype, cilp->protocol, sa, cilp->portal_id);
        if (error != 0) {
                free(sa, M_SONAME);
                CFISCSI_DEBUG("icl_listen_add, error %d", error);
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "icl_listen_add failed, error %d", error);
                ci->status = CTL_ISCSI_ERROR;
                return;
        }

        ci->status = CTL_ISCSI_OK;
}

static void
cfiscsi_ioctl_accept(struct ctl_iscsi *ci)
{
        struct ctl_iscsi_accept_params *ciap;
        struct cfiscsi_session *cs;
        int error;

        ciap = (struct ctl_iscsi_accept_params *)&(ci->data);

        mtx_lock(&cfiscsi_softc.lock);
        for (;;) {
                TAILQ_FOREACH(cs, &cfiscsi_softc.sessions, cs_next) {
                        if (cs->cs_waiting_for_ctld)
                                break;
                }
                if (cs != NULL)
                        break;
                error = cv_wait_sig(&cfiscsi_softc.accept_cv, &cfiscsi_softc.lock);
                if (error != 0) {
                        mtx_unlock(&cfiscsi_softc.lock);
                        snprintf(ci->error_str, sizeof(ci->error_str), "interrupted");
                        ci->status = CTL_ISCSI_ERROR;
                        return;
                }
        }
        mtx_unlock(&cfiscsi_softc.lock);

        cs->cs_waiting_for_ctld = false;
        cs->cs_login_phase = true;

        ciap->connection_id = cs->cs_id;
        ciap->portal_id = cs->cs_portal_id;
        ciap->initiator_addrlen = cs->cs_initiator_sa->sa_len;
        error = copyout(cs->cs_initiator_sa, ciap->initiator_addr,
            cs->cs_initiator_sa->sa_len);
        if (error != 0) {
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "copyout failed with error %d", error);
                ci->status = CTL_ISCSI_ERROR;
                return;
        }

        ci->status = CTL_ISCSI_OK;
}

static void
cfiscsi_ioctl_send(struct ctl_iscsi *ci)
{
        struct ctl_iscsi_send_params *cisp;
        struct cfiscsi_session *cs;
        struct icl_pdu *ip;
        size_t datalen;
        void *data;
        int error;

        cisp = (struct ctl_iscsi_send_params *)&(ci->data);

        mtx_lock(&cfiscsi_softc.lock);
        TAILQ_FOREACH(cs, &cfiscsi_softc.sessions, cs_next) {
                if (cs->cs_id == cisp->connection_id)
                        break;
        }
        if (cs == NULL) {
                mtx_unlock(&cfiscsi_softc.lock);
                snprintf(ci->error_str, sizeof(ci->error_str), "connection not found");
                ci->status = CTL_ISCSI_ERROR;
                return;
        }
        mtx_unlock(&cfiscsi_softc.lock);

#if 0
        if (cs->cs_login_phase == false)
                return (EBUSY);
#endif

        if (cs->cs_terminating) {
                snprintf(ci->error_str, sizeof(ci->error_str), "connection is terminating");
                ci->status = CTL_ISCSI_ERROR;
                return;
        }

        datalen = cisp->data_segment_len;
        /*
         * XXX
         */
        //if (datalen > CFISCSI_MAX_DATA_SEGMENT_LENGTH) {
        if (datalen > 65535) {
                snprintf(ci->error_str, sizeof(ci->error_str), "data segment too big");
                ci->status = CTL_ISCSI_ERROR;
                return;
        }
        if (datalen > 0) {
                data = malloc(datalen, M_CFISCSI, M_WAITOK);
                error = copyin(cisp->data_segment, data, datalen);
                if (error != 0) {
                        free(data, M_CFISCSI);
                        snprintf(ci->error_str, sizeof(ci->error_str), "copyin error %d", error);
                        ci->status = CTL_ISCSI_ERROR;
                        return;
                }
        }

        ip = icl_pdu_new(cs->cs_conn, M_WAITOK);
        memcpy(ip->ip_bhs, cisp->bhs, sizeof(*ip->ip_bhs));
        if (datalen > 0) {
                icl_pdu_append_data(ip, data, datalen, M_WAITOK);
                free(data, M_CFISCSI);
        }
        CFISCSI_SESSION_LOCK(cs);
        icl_pdu_queue(ip);
        CFISCSI_SESSION_UNLOCK(cs);
        ci->status = CTL_ISCSI_OK;
}

static void
cfiscsi_ioctl_receive(struct ctl_iscsi *ci)
{
        struct ctl_iscsi_receive_params *cirp;
        struct cfiscsi_session *cs;
        struct icl_pdu *ip;
        void *data;
        int error;

        cirp = (struct ctl_iscsi_receive_params *)&(ci->data);

        mtx_lock(&cfiscsi_softc.lock);
        TAILQ_FOREACH(cs, &cfiscsi_softc.sessions, cs_next) {
                if (cs->cs_id == cirp->connection_id)
                        break;
        }
        if (cs == NULL) {
                mtx_unlock(&cfiscsi_softc.lock);
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "connection not found");
                ci->status = CTL_ISCSI_ERROR;
                return;
        }
        mtx_unlock(&cfiscsi_softc.lock);

#if 0
        if (is->is_login_phase == false)
                return (EBUSY);
#endif

        CFISCSI_SESSION_LOCK(cs);
        while (cs->cs_login_pdu == NULL && cs->cs_terminating == false) {
                error = cv_wait_sig(&cs->cs_login_cv, &cs->cs_lock);
                if (error != 0) {
                        CFISCSI_SESSION_UNLOCK(cs);
                        snprintf(ci->error_str, sizeof(ci->error_str),
                            "interrupted by signal");
                        ci->status = CTL_ISCSI_ERROR;
                        return;
                }
        }

        if (cs->cs_terminating) {
                CFISCSI_SESSION_UNLOCK(cs);
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "connection terminating");
                ci->status = CTL_ISCSI_ERROR;
                return;
        }
        ip = cs->cs_login_pdu;
        cs->cs_login_pdu = NULL;
        CFISCSI_SESSION_UNLOCK(cs);

        if (ip->ip_data_len > cirp->data_segment_len) {
                icl_pdu_free(ip);
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "data segment too big");
                ci->status = CTL_ISCSI_ERROR;
                return;
        }

        copyout(ip->ip_bhs, cirp->bhs, sizeof(*ip->ip_bhs));
        if (ip->ip_data_len > 0) {
                data = malloc(ip->ip_data_len, M_CFISCSI, M_WAITOK);
                icl_pdu_get_data(ip, 0, data, ip->ip_data_len);
                copyout(data, cirp->data_segment, ip->ip_data_len);
                free(data, M_CFISCSI);
        }

        icl_pdu_free(ip);
        ci->status = CTL_ISCSI_OK;
}

#endif /* !ICL_KERNEL_PROXY */

static void
cfiscsi_ioctl_port_create(struct ctl_req *req)
{
        struct cfiscsi_target *ct;
        struct ctl_port *port;
        const char *target, *alias, *val;
        struct scsi_vpd_id_descriptor *desc;
        int retval, len, idlen;
        uint16_t tag;

        target = dnvlist_get_string(req->args_nvl, "cfiscsi_target", NULL);
        if (target == NULL) {
                req->status = CTL_LUN_ERROR;
                snprintf(req->error_str, sizeof(req->error_str),
                    "Missing required argument: cfiscsi_target");
                return;
        }

        val = dnvlist_get_string(req->args_nvl, "cfiscsi_portal_group_tag",
            NULL);
        if (val == NULL) {
                req->status = CTL_LUN_ERROR;
                snprintf(req->error_str, sizeof(req->error_str),
                    "Missing required argument: cfiscsi_portal_group_tag");
                return;
        }

        alias = dnvlist_get_string(req->args_nvl, "cfiscsi_target_alias", NULL);

        tag = strtoul(val, NULL, 0);
        ct = cfiscsi_target_find_or_create(&cfiscsi_softc, target, alias, tag);
        if (ct == NULL) {
                req->status = CTL_LUN_ERROR;
                snprintf(req->error_str, sizeof(req->error_str),
                    "failed to create target \"%s\"", target);
                return;
        }
        if (ct->ct_state == CFISCSI_TARGET_STATE_ACTIVE) {
                req->status = CTL_LUN_ERROR;
                snprintf(req->error_str, sizeof(req->error_str),
                    "target \"%s\" for portal group tag %u already exists",
                    target, tag);
                cfiscsi_target_release(ct);
                return;
        }
        port = &ct->ct_port;
        // WAT
        if (ct->ct_state == CFISCSI_TARGET_STATE_DYING)
                goto done;

        port->frontend = &cfiscsi_frontend;
        port->port_type = CTL_PORT_ISCSI;
        /* XXX KDM what should the real number be here? */
        port->num_requested_ctl_io = 4096;
        port->port_name = "iscsi";
        port->physical_port = (int)tag;
        port->virtual_port = ct->ct_target_id;
        port->port_online = cfiscsi_online;
        port->port_offline = cfiscsi_offline;
        port->port_info = cfiscsi_info;
        port->onoff_arg = ct;
        port->fe_datamove = cfiscsi_datamove;
        port->fe_done = cfiscsi_done;
        port->targ_port = -1;
        port->options = nvlist_clone(req->args_nvl);

        /* Generate Port ID. */
        idlen = strlen(target) + strlen(",t,0x0001") + 1;
        idlen = roundup2(idlen, 4);
        len = sizeof(struct scsi_vpd_device_id) + idlen;
        port->port_devid = malloc(sizeof(struct ctl_devid) + len,
            M_CTL, M_WAITOK | M_ZERO);
        port->port_devid->len = len;
        desc = (struct scsi_vpd_id_descriptor *)port->port_devid->data;
        desc->proto_codeset = (SCSI_PROTO_ISCSI << 4) | SVPD_ID_CODESET_UTF8;
        desc->id_type = SVPD_ID_PIV | SVPD_ID_ASSOC_PORT |
            SVPD_ID_TYPE_SCSI_NAME;
        desc->length = idlen;
        snprintf(desc->identifier, idlen, "%s,t,0x%4.4x", target, tag);

        /* Generate Target ID. */
        idlen = strlen(target) + 1;
        idlen = roundup2(idlen, 4);
        len = sizeof(struct scsi_vpd_device_id) + idlen;
        port->target_devid = malloc(sizeof(struct ctl_devid) + len,
            M_CTL, M_WAITOK | M_ZERO);
        port->target_devid->len = len;
        desc = (struct scsi_vpd_id_descriptor *)port->target_devid->data;
        desc->proto_codeset = (SCSI_PROTO_ISCSI << 4) | SVPD_ID_CODESET_UTF8;
        desc->id_type = SVPD_ID_PIV | SVPD_ID_ASSOC_TARGET |
            SVPD_ID_TYPE_SCSI_NAME;
        desc->length = idlen;
        strlcpy(desc->identifier, target, idlen);

        retval = ctl_port_register(port);
        if (retval != 0) {
                free(port->port_devid, M_CFISCSI);
                free(port->target_devid, M_CFISCSI);
                cfiscsi_target_release(ct);
                req->status = CTL_LUN_ERROR;
                snprintf(req->error_str, sizeof(req->error_str),
                    "ctl_port_register() failed with error %d", retval);
                return;
        }
done:
        ct->ct_state = CFISCSI_TARGET_STATE_ACTIVE;
        req->status = CTL_LUN_OK;
        req->result_nvl = nvlist_create(0);
        nvlist_add_number(req->result_nvl, "port_id", port->targ_port);
}

static void
cfiscsi_ioctl_port_remove(struct ctl_req *req)
{
        struct cfiscsi_target *ct;
        const char *target, *val;
        uint16_t tag;

        target = dnvlist_get_string(req->args_nvl, "cfiscsi_target", NULL);
        if (target == NULL) {
                req->status = CTL_LUN_ERROR;
                snprintf(req->error_str, sizeof(req->error_str),
                    "Missing required argument: cfiscsi_target");
                return;
        }

        val = dnvlist_get_string(req->args_nvl, "cfiscsi_portal_group_tag",
            NULL);
        if (val == NULL) {
                req->status = CTL_LUN_ERROR;
                snprintf(req->error_str, sizeof(req->error_str),
                    "Missing required argument: cfiscsi_portal_group_tag");
                return;
        }

        tag = strtoul(val, NULL, 0);
        ct = cfiscsi_target_find(&cfiscsi_softc, target, tag);
        if (ct == NULL) {
                req->status = CTL_LUN_ERROR;
                snprintf(req->error_str, sizeof(req->error_str),
                    "can't find target \"%s\"", target);
                return;
        }

        ct->ct_state = CFISCSI_TARGET_STATE_DYING;
        ctl_port_offline(&ct->ct_port);
        cfiscsi_target_release(ct);
        cfiscsi_target_release(ct);
        req->status = CTL_LUN_OK;
}

static int
cfiscsi_ioctl(struct cdev *dev,
    u_long cmd, caddr_t addr, int flag, struct thread *td)
{
        struct ctl_iscsi *ci;
        struct ctl_req *req;

        if (cmd == CTL_PORT_REQ) {
                req = (struct ctl_req *)addr;
                switch (req->reqtype) {
                case CTL_REQ_CREATE:
                        cfiscsi_ioctl_port_create(req);
                        break;
                case CTL_REQ_REMOVE:
                        cfiscsi_ioctl_port_remove(req);
                        break;
                default:
                        req->status = CTL_LUN_ERROR;
                        snprintf(req->error_str, sizeof(req->error_str),
                            "Unsupported request type %d", req->reqtype);
                }
                return (0);
        }

        if (cmd != CTL_ISCSI)
                return (ENOTTY);

        ci = (struct ctl_iscsi *)addr;
        switch (ci->type) {
        case CTL_ISCSI_HANDOFF:
                cfiscsi_ioctl_handoff(ci);
                break;
        case CTL_ISCSI_LIST:
                cfiscsi_ioctl_list(ci);
                break;
        case CTL_ISCSI_LOGOUT:
                cfiscsi_ioctl_logout(ci);
                break;
        case CTL_ISCSI_TERMINATE:
                cfiscsi_ioctl_terminate(ci);
                break;
        case CTL_ISCSI_LIMITS:
                cfiscsi_ioctl_limits(ci);
                break;
#ifdef ICL_KERNEL_PROXY
        case CTL_ISCSI_LISTEN:
                cfiscsi_ioctl_listen(ci);
                break;
        case CTL_ISCSI_ACCEPT:
                cfiscsi_ioctl_accept(ci);
                break;
        case CTL_ISCSI_SEND:
                cfiscsi_ioctl_send(ci);
                break;
        case CTL_ISCSI_RECEIVE:
                cfiscsi_ioctl_receive(ci);
                break;
#else
        case CTL_ISCSI_LISTEN:
        case CTL_ISCSI_ACCEPT:
        case CTL_ISCSI_SEND:
        case CTL_ISCSI_RECEIVE:
                ci->status = CTL_ISCSI_ERROR;
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "%s: CTL compiled without ICL_KERNEL_PROXY",
                    __func__);
                break;
#endif /* !ICL_KERNEL_PROXY */
        default:
                ci->status = CTL_ISCSI_ERROR;
                snprintf(ci->error_str, sizeof(ci->error_str),
                    "%s: invalid iSCSI request type %d", __func__, ci->type);
                break;
        }

        return (0);
}

static void
cfiscsi_target_hold(struct cfiscsi_target *ct)
{

        refcount_acquire(&ct->ct_refcount);
}

static void
cfiscsi_target_release(struct cfiscsi_target *ct)
{
        struct cfiscsi_softc *softc;

        softc = ct->ct_softc;
        mtx_lock(&softc->lock);
        if (refcount_release(&ct->ct_refcount)) {
                TAILQ_REMOVE(&softc->targets, ct, ct_next);
                mtx_unlock(&softc->lock);
                if (ct->ct_state != CFISCSI_TARGET_STATE_INVALID) {
                        ct->ct_state = CFISCSI_TARGET_STATE_INVALID;
                        if (ctl_port_deregister(&ct->ct_port) != 0)
                                printf("%s: ctl_port_deregister() failed\n",
                                    __func__);
                }
                free(ct, M_CFISCSI);

                return;
        }
        mtx_unlock(&softc->lock);
}

static struct cfiscsi_target *
cfiscsi_target_find(struct cfiscsi_softc *softc, const char *name, uint16_t tag)
{
        struct cfiscsi_target *ct;

        mtx_lock(&softc->lock);
        TAILQ_FOREACH(ct, &softc->targets, ct_next) {
                if (ct->ct_tag != tag ||
                    strcmp(name, ct->ct_name) != 0 ||
                    ct->ct_state != CFISCSI_TARGET_STATE_ACTIVE)
                        continue;
                cfiscsi_target_hold(ct);
                mtx_unlock(&softc->lock);
                return (ct);
        }
        mtx_unlock(&softc->lock);

        return (NULL);
}

static struct cfiscsi_target *
cfiscsi_target_find_or_create(struct cfiscsi_softc *softc, const char *name,
    const char *alias, uint16_t tag)
{
        struct cfiscsi_target *ct, *newct;

        if (name[0] == '\0' || strlen(name) >= CTL_ISCSI_NAME_LEN)
                return (NULL);

        newct = malloc(sizeof(*newct), M_CFISCSI, M_WAITOK | M_ZERO);

        mtx_lock(&softc->lock);
        TAILQ_FOREACH(ct, &softc->targets, ct_next) {
                if (ct->ct_tag != tag ||
                    strcmp(name, ct->ct_name) != 0 ||
                    ct->ct_state == CFISCSI_TARGET_STATE_INVALID)
                        continue;
                cfiscsi_target_hold(ct);
                mtx_unlock(&softc->lock);
                free(newct, M_CFISCSI);
                return (ct);
        }

        strlcpy(newct->ct_name, name, sizeof(newct->ct_name));
        if (alias != NULL)
                strlcpy(newct->ct_alias, alias, sizeof(newct->ct_alias));
        newct->ct_tag = tag;
        refcount_init(&newct->ct_refcount, 1);
        newct->ct_softc = softc;
        if (TAILQ_EMPTY(&softc->targets))
                softc->last_target_id = 0;
        newct->ct_target_id = ++softc->last_target_id;
        TAILQ_INSERT_TAIL(&softc->targets, newct, ct_next);
        mtx_unlock(&softc->lock);

        return (newct);
}

static void
cfiscsi_pdu_done(struct icl_pdu *ip, int error)
{

        if (error != 0)
                ; // XXX: Do something on error?
        ((ctl_ref)ip->ip_prv0)(ip->ip_prv1, -1);
}

static void
cfiscsi_datamove_in(union ctl_io *io)
{
        struct cfiscsi_session *cs;
        struct icl_pdu *request, *response;
        const struct iscsi_bhs_scsi_command *bhssc;
        struct iscsi_bhs_data_in *bhsdi;
        struct ctl_sg_entry ctl_sg_entry, *ctl_sglist;
        size_t len, expected_len, sg_len, buffer_offset;
        size_t max_send_data_segment_length;
        const char *sg_addr;
        icl_pdu_cb cb;
        int ctl_sg_count, error, i;

        request = PRIV_REQUEST(io);
        cs = PDU_SESSION(request);

        bhssc = (const struct iscsi_bhs_scsi_command *)request->ip_bhs;
        KASSERT((bhssc->bhssc_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
            ISCSI_BHS_OPCODE_SCSI_COMMAND,
            ("bhssc->bhssc_opcode != ISCSI_BHS_OPCODE_SCSI_COMMAND"));

        if (io->scsiio.kern_sg_entries > 0) {
                ctl_sglist = (struct ctl_sg_entry *)io->scsiio.kern_data_ptr;
                ctl_sg_count = io->scsiio.kern_sg_entries;
        } else {
                ctl_sglist = &ctl_sg_entry;
                ctl_sglist->addr = io->scsiio.kern_data_ptr;
                ctl_sglist->len = io->scsiio.kern_data_len;
                ctl_sg_count = 1;
        }

        /*
         * This is the offset within the current SCSI command; for the first
         * call to cfiscsi_datamove() it will be 0, and for subsequent ones
         * it will be the sum of lengths of previous ones.
         */
        buffer_offset = io->scsiio.kern_rel_offset;

        /*
         * This is the transfer length expected by the initiator.  It can be
         * different from the amount of data from the SCSI point of view.
         */
        expected_len = ntohl(bhssc->bhssc_expected_data_transfer_length);

        /*
         * If the transfer is outside of expected length -- we are done.
         */
        if (buffer_offset >= expected_len) {
#if 0
                CFISCSI_SESSION_DEBUG(cs, "buffer_offset = %zd, "
                    "already sent the expected len", buffer_offset);
#endif
                ctl_datamove_done(io, true);
                return;
        }

        if (io->scsiio.kern_data_ref != NULL)
                cb = cfiscsi_pdu_done;
        else
                cb = NULL;

        i = 0;
        sg_addr = NULL;
        sg_len = 0;
        response = NULL;
        bhsdi = NULL;
        if (cs->cs_conn->ic_hw_isomax != 0)
                max_send_data_segment_length = cs->cs_conn->ic_hw_isomax;
        else
                max_send_data_segment_length =
                    cs->cs_conn->ic_max_send_data_segment_length;
        for (;;) {
                if (response == NULL) {
                        response = cfiscsi_pdu_new_response(request, M_NOWAIT);
                        if (response == NULL) {
                                CFISCSI_SESSION_WARN(cs, "failed to "
                                    "allocate memory; dropping connection");
                                ctl_set_busy(&io->scsiio);
                                ctl_datamove_done(io, true);
                                cfiscsi_session_terminate(cs);
                                return;
                        }
                        bhsdi = (struct iscsi_bhs_data_in *)response->ip_bhs;
                        bhsdi->bhsdi_opcode = ISCSI_BHS_OPCODE_SCSI_DATA_IN;
                        bhsdi->bhsdi_initiator_task_tag =
                            bhssc->bhssc_initiator_task_tag;
                        bhsdi->bhsdi_target_transfer_tag = 0xffffffff;
                        bhsdi->bhsdi_datasn = htonl(PRIV_EXPDATASN(io));
                        bhsdi->bhsdi_buffer_offset = htonl(buffer_offset);
                }

                KASSERT(i < ctl_sg_count, ("i >= ctl_sg_count"));
                if (sg_len == 0) {
                        sg_addr = ctl_sglist[i].addr;
                        sg_len = ctl_sglist[i].len;
                        KASSERT(sg_len > 0, ("sg_len <= 0"));
                }

                len = sg_len;

                /*
                 * Truncate to maximum data segment length.
                 */
                KASSERT(response->ip_data_len < max_send_data_segment_length,
                    ("ip_data_len %zd >= max_send_data_segment_length %zd",
                    response->ip_data_len, max_send_data_segment_length));
                if (response->ip_data_len + len > max_send_data_segment_length) {
                        len = max_send_data_segment_length - response->ip_data_len;
                        KASSERT(len <= sg_len, ("len %zd > sg_len %zd",
                            len, sg_len));
                }

                /*
                 * Truncate to expected data transfer length.
                 */
                KASSERT(buffer_offset + response->ip_data_len < expected_len,
                    ("buffer_offset %zd + ip_data_len %zd >= expected_len %zd",
                    buffer_offset, response->ip_data_len, expected_len));
                if (buffer_offset + response->ip_data_len + len > expected_len) {
                        CFISCSI_SESSION_DEBUG(cs, "truncating from %zd "
                            "to expected data transfer length %zd",
                            buffer_offset + response->ip_data_len + len, expected_len);
                        len = expected_len - (buffer_offset + response->ip_data_len);
                        KASSERT(len <= sg_len, ("len %zd > sg_len %zd",
                            len, sg_len));
                }

                error = icl_pdu_append_data(response, sg_addr, len,
                    M_NOWAIT | (cb ? ICL_NOCOPY : 0));
                if (error != 0) {
                        CFISCSI_SESSION_WARN(cs, "failed to "
                            "allocate memory; dropping connection");
                        icl_pdu_free(response);
                        ctl_set_busy(&io->scsiio);
                        ctl_datamove_done(io, true);
                        cfiscsi_session_terminate(cs);
                        return;
                }
                sg_addr += len;
                sg_len -= len;
                io->scsiio.kern_data_resid -= len;

                KASSERT(buffer_offset + response->ip_data_len <= expected_len,
                    ("buffer_offset %zd + ip_data_len %zd > expected_len %zd",
                    buffer_offset, response->ip_data_len, expected_len));
                if (buffer_offset + response->ip_data_len == expected_len) {
                        /*
                         * Already have the amount of data the initiator wanted.
                         */
                        break;
                }

                if (sg_len == 0) {
                        /*
                         * End of scatter-gather segment;
                         * proceed to the next one...
                         */
                        if (i == ctl_sg_count - 1) {
                                /*
                                 * ... unless this was the last one.
                                 */
                                break;
                        }
                        i++;
                }

                if (response->ip_data_len == max_send_data_segment_length) {
                        /*
                         * Can't stuff more data into the current PDU;
                         * queue it.  Note that's not enough to check
                         * for kern_data_resid == 0 instead; there
                         * may be several Data-In PDUs for the final
                         * call to cfiscsi_datamove(), and we want
                         * to set the F flag only on the last of them.
                         */
                        buffer_offset += response->ip_data_len;
                        if (buffer_offset == io->scsiio.kern_total_len ||
                            buffer_offset == expected_len) {
                                buffer_offset -= response->ip_data_len;
                                break;
                        }
                        PRIV_EXPDATASN(io) += howmany(response->ip_data_len,
                            cs->cs_conn->ic_max_send_data_segment_length);
                        if (cb != NULL) {
                                response->ip_prv0 = io->scsiio.kern_data_ref;
                                response->ip_prv1 = io->scsiio.kern_data_arg;
                                io->scsiio.kern_data_ref(io->scsiio.kern_data_arg, 1);
                        }
                        cfiscsi_pdu_queue_cb(response, cb);
                        response = NULL;
                        bhsdi = NULL;
                }
        }
        if (response != NULL) {
                buffer_offset += response->ip_data_len;
                if (buffer_offset == io->scsiio.kern_total_len ||
                    buffer_offset == expected_len) {
                        bhsdi->bhsdi_flags |= BHSDI_FLAGS_F;
                        if (io->io_hdr.status == CTL_SUCCESS) {
                                bhsdi->bhsdi_flags |= BHSDI_FLAGS_S;
                                if (io->scsiio.kern_total_len <
                                    ntohl(bhssc->bhssc_expected_data_transfer_length)) {
                                        bhsdi->bhsdi_flags |= BHSSR_FLAGS_RESIDUAL_UNDERFLOW;
                                        bhsdi->bhsdi_residual_count =
                                            htonl(ntohl(bhssc->bhssc_expected_data_transfer_length) -
                                            io->scsiio.kern_total_len);
                                } else if (io->scsiio.kern_total_len >
                                    ntohl(bhssc->bhssc_expected_data_transfer_length)) {
                                        bhsdi->bhsdi_flags |= BHSSR_FLAGS_RESIDUAL_OVERFLOW;
                                        bhsdi->bhsdi_residual_count =
                                            htonl(io->scsiio.kern_total_len -
                                            ntohl(bhssc->bhssc_expected_data_transfer_length));
                                }
                                bhsdi->bhsdi_status = io->scsiio.scsi_status;
                                io->io_hdr.flags |= CTL_FLAG_STATUS_SENT;
                        }
                }
                KASSERT(response->ip_data_len > 0, ("sending empty Data-In"));
                PRIV_EXPDATASN(io) += howmany(response->ip_data_len,
                    cs->cs_conn->ic_max_send_data_segment_length);
                if (cb != NULL) {
                        response->ip_prv0 = io->scsiio.kern_data_ref;
                        response->ip_prv1 = io->scsiio.kern_data_arg;
                        io->scsiio.kern_data_ref(io->scsiio.kern_data_arg, 1);
                }
                cfiscsi_pdu_queue_cb(response, cb);
        }

        ctl_datamove_done(io, true);
}

static void
cfiscsi_datamove_out(union ctl_io *io)
{
        struct cfiscsi_session *cs;
        struct icl_pdu *request, *response;
        const struct iscsi_bhs_scsi_command *bhssc;
        struct iscsi_bhs_r2t *bhsr2t;
        struct cfiscsi_data_wait *cdw;
        struct ctl_sg_entry ctl_sg_entry, *ctl_sglist;
        uint32_t expected_len, datamove_len, r2t_off, r2t_len;
        uint32_t target_transfer_tag;
        bool done;

        request = PRIV_REQUEST(io);
        cs = PDU_SESSION(request);

        bhssc = (const struct iscsi_bhs_scsi_command *)request->ip_bhs;
        KASSERT((bhssc->bhssc_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
            ISCSI_BHS_OPCODE_SCSI_COMMAND,
            ("bhssc->bhssc_opcode != ISCSI_BHS_OPCODE_SCSI_COMMAND"));

        /*
         * Complete write underflow.  Not a single byte to read.  Return.
         */
        expected_len = ntohl(bhssc->bhssc_expected_data_transfer_length);
        if (io->scsiio.kern_rel_offset >= expected_len) {
                ctl_datamove_done(io, true);
                return;
        }

        datamove_len = MIN(io->scsiio.kern_data_len,
            expected_len - io->scsiio.kern_rel_offset);

        target_transfer_tag =
            atomic_fetchadd_32(&cs->cs_target_transfer_tag, 1);
        if (target_transfer_tag == 0xffffffff) {
                target_transfer_tag =
                    atomic_fetchadd_32(&cs->cs_target_transfer_tag, 1);
        }
        cdw = cfiscsi_data_wait_new(cs, io, bhssc->bhssc_initiator_task_tag,
            &target_transfer_tag);
        if (cdw == NULL) {
                CFISCSI_SESSION_WARN(cs, "failed to "
                    "allocate memory; dropping connection");
                ctl_set_busy(&io->scsiio);
                ctl_datamove_done(io, true);
                cfiscsi_session_terminate(cs);
                return;
        }
#if 0
        CFISCSI_SESSION_DEBUG(cs, "expecting Data-Out with initiator "
            "task tag 0x%x, target transfer tag 0x%x",
            bhssc->bhssc_initiator_task_tag, target_transfer_tag);
#endif

        cdw->cdw_ctl_io = io;
        cdw->cdw_target_transfer_tag = target_transfer_tag;
        cdw->cdw_initiator_task_tag = bhssc->bhssc_initiator_task_tag;
        cdw->cdw_r2t_end = datamove_len;
        cdw->cdw_datasn = 0;

        /* Set initial data pointer for the CDW respecting ext_data_filled. */
        if (io->scsiio.kern_sg_entries > 0) {
                ctl_sglist = (struct ctl_sg_entry *)io->scsiio.kern_data_ptr;
        } else {
                ctl_sglist = &ctl_sg_entry;
                ctl_sglist->addr = io->scsiio.kern_data_ptr;
                ctl_sglist->len = datamove_len;
        }
        cdw->cdw_sg_index = 0;
        cdw->cdw_sg_addr = ctl_sglist[cdw->cdw_sg_index].addr;
        cdw->cdw_sg_len = ctl_sglist[cdw->cdw_sg_index].len;
        r2t_off = io->scsiio.ext_data_filled;
        while (r2t_off > 0) {
                if (r2t_off >= cdw->cdw_sg_len) {
                        r2t_off -= cdw->cdw_sg_len;
                        cdw->cdw_sg_index++;
                        cdw->cdw_sg_addr = ctl_sglist[cdw->cdw_sg_index].addr;
                        cdw->cdw_sg_len = ctl_sglist[cdw->cdw_sg_index].len;
                        continue;
                }
                cdw->cdw_sg_addr += r2t_off;
                cdw->cdw_sg_len -= r2t_off;
                r2t_off = 0;
        }

        if (cs->cs_immediate_data &&
            io->scsiio.kern_rel_offset + io->scsiio.ext_data_filled <
            icl_pdu_data_segment_length(request)) {
                done = cfiscsi_handle_data_segment(request, cdw);
                if (done) {
                        cfiscsi_data_wait_free(cs, cdw);
                        ctl_datamove_done(io, true);
                        return;
                }
        }

        r2t_off = io->scsiio.kern_rel_offset + io->scsiio.ext_data_filled;
        r2t_len = MIN(datamove_len - io->scsiio.ext_data_filled,
            cs->cs_max_burst_length);
        cdw->cdw_r2t_end = io->scsiio.ext_data_filled + r2t_len;

        CFISCSI_SESSION_LOCK(cs);
        if (cs->cs_terminating_tasks) {
                CFISCSI_SESSION_UNLOCK(cs);
                KASSERT((io->io_hdr.flags & CTL_FLAG_ABORT) != 0,
                    ("%s: I/O request %p on termating session %p not aborted",
                    __func__, io, cs));
                CFISCSI_SESSION_WARN(cs, "aborting data_wait for aborted I/O");
                cfiscsi_data_wait_abort(cs, cdw, 44);
                return;
        }
        TAILQ_INSERT_TAIL(&cs->cs_waiting_for_data_out, cdw, cdw_next);
        CFISCSI_SESSION_UNLOCK(cs);

        /*
         * XXX: We should limit the number of outstanding R2T PDUs
         *      per task to MaxOutstandingR2T.
         */
        response = cfiscsi_pdu_new_response(request, M_NOWAIT);
        if (response == NULL) {
                CFISCSI_SESSION_WARN(cs, "failed to "
                    "allocate memory; dropping connection");
                ctl_set_busy(&io->scsiio);
                ctl_datamove_done(io, true);
                cfiscsi_session_terminate(cs);
                return;
        }
        io->io_hdr.flags |= CTL_FLAG_DMA_INPROG;
        bhsr2t = (struct iscsi_bhs_r2t *)response->ip_bhs;
        bhsr2t->bhsr2t_opcode = ISCSI_BHS_OPCODE_R2T;
        bhsr2t->bhsr2t_flags = 0x80;
        bhsr2t->bhsr2t_lun = bhssc->bhssc_lun;
        bhsr2t->bhsr2t_initiator_task_tag = bhssc->bhssc_initiator_task_tag;
        bhsr2t->bhsr2t_target_transfer_tag = target_transfer_tag;
        /*
         * XXX: Here we assume that cfiscsi_datamove() won't ever
         *      be running concurrently on several CPUs for a given
         *      command.
         */
        bhsr2t->bhsr2t_r2tsn = htonl(PRIV_R2TSN(io)++);
        /*
         * This is the offset within the current SCSI command;
         * i.e. for the first call of datamove(), it will be 0,
         * and for subsequent ones it will be the sum of lengths
         * of previous ones.
         *
         * The ext_data_filled is to account for unsolicited
         * (immediate) data that might have already arrived.
         */
        bhsr2t->bhsr2t_buffer_offset = htonl(r2t_off);
        /*
         * This is the total length (sum of S/G lengths) this call
         * to cfiscsi_datamove() is supposed to handle, limited by
         * MaxBurstLength.
         */
        bhsr2t->bhsr2t_desired_data_transfer_length = htonl(r2t_len);
        cfiscsi_pdu_queue(response);
}

static void
cfiscsi_datamove(union ctl_io *io)
{

        if ((io->io_hdr.flags & CTL_FLAG_DATA_MASK) == CTL_FLAG_DATA_IN)
                cfiscsi_datamove_in(io);
        else {
                /* We hadn't received anything during this datamove yet. */
                io->scsiio.ext_data_filled = 0;
                cfiscsi_datamove_out(io);
        }
}

static void
cfiscsi_scsi_command_done(union ctl_io *io)
{
        struct icl_pdu *request, *response;
        struct iscsi_bhs_scsi_command *bhssc;
        struct iscsi_bhs_scsi_response *bhssr;
#ifdef DIAGNOSTIC
        struct cfiscsi_data_wait *cdw;
        struct cfiscsi_session *cs;
#endif
        uint16_t sense_length;

        request = PRIV_REQUEST(io);
        bhssc = (struct iscsi_bhs_scsi_command *)request->ip_bhs;
        KASSERT((bhssc->bhssc_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
            ISCSI_BHS_OPCODE_SCSI_COMMAND,
            ("replying to wrong opcode 0x%x", bhssc->bhssc_opcode));

        //CFISCSI_SESSION_DEBUG(cs, "initiator task tag 0x%x",
        //    bhssc->bhssc_initiator_task_tag);

#ifdef DIAGNOSTIC
        cs = PDU_SESSION(request);
        CFISCSI_SESSION_LOCK(cs);
        TAILQ_FOREACH(cdw, &cs->cs_waiting_for_data_out, cdw_next)
                KASSERT(bhssc->bhssc_initiator_task_tag !=
                    cdw->cdw_initiator_task_tag, ("dangling cdw"));
        CFISCSI_SESSION_UNLOCK(cs);
#endif

        /*
         * Do not return status for aborted commands.
         * There are exceptions, but none supported by CTL yet.
         */
        if (((io->io_hdr.flags & CTL_FLAG_ABORT) &&
             (io->io_hdr.flags & CTL_FLAG_ABORT_STATUS) == 0) ||
            (io->io_hdr.flags & CTL_FLAG_STATUS_SENT)) {
                ctl_free_io(io);
                icl_pdu_free(request);
                return;
        }

        response = cfiscsi_pdu_new_response(request, M_WAITOK);
        bhssr = (struct iscsi_bhs_scsi_response *)response->ip_bhs;
        bhssr->bhssr_opcode = ISCSI_BHS_OPCODE_SCSI_RESPONSE;
        bhssr->bhssr_flags = 0x80;
        /*
         * XXX: We don't deal with bidirectional under/overflows;
         *      does anything actually support those?
         */
        if (io->scsiio.kern_total_len <
            ntohl(bhssc->bhssc_expected_data_transfer_length)) {
                bhssr->bhssr_flags |= BHSSR_FLAGS_RESIDUAL_UNDERFLOW;
                bhssr->bhssr_residual_count =
                    htonl(ntohl(bhssc->bhssc_expected_data_transfer_length) -
                    io->scsiio.kern_total_len);
                //CFISCSI_SESSION_DEBUG(cs, "underflow; residual count %d",
                //    ntohl(bhssr->bhssr_residual_count));
        } else if (io->scsiio.kern_total_len >
            ntohl(bhssc->bhssc_expected_data_transfer_length)) {
                bhssr->bhssr_flags |= BHSSR_FLAGS_RESIDUAL_OVERFLOW;
                bhssr->bhssr_residual_count = htonl(io->scsiio.kern_total_len -
                    ntohl(bhssc->bhssc_expected_data_transfer_length));
                //CFISCSI_SESSION_DEBUG(cs, "overflow; residual count %d",
                //    ntohl(bhssr->bhssr_residual_count));
        }
        bhssr->bhssr_response = BHSSR_RESPONSE_COMMAND_COMPLETED;
        bhssr->bhssr_status = io->scsiio.scsi_status;
        bhssr->bhssr_initiator_task_tag = bhssc->bhssc_initiator_task_tag;
        bhssr->bhssr_expdatasn = htonl(PRIV_EXPDATASN(io));

        if (io->scsiio.sense_len > 0) {
#if 0
                CFISCSI_SESSION_DEBUG(cs, "returning %d bytes of sense data",
                    io->scsiio.sense_len);
#endif
                sense_length = htons(io->scsiio.sense_len);
                icl_pdu_append_data(response,
                    &sense_length, sizeof(sense_length), M_WAITOK);
                icl_pdu_append_data(response,
                    &io->scsiio.sense_data, io->scsiio.sense_len, M_WAITOK);
        }

        ctl_free_io(io);
        icl_pdu_free(request);
        cfiscsi_pdu_queue(response);
}

static void
cfiscsi_task_management_done(union ctl_io *io)
{
        struct icl_pdu *request, *response;
        struct iscsi_bhs_task_management_request *bhstmr;
        struct iscsi_bhs_task_management_response *bhstmr2;
        struct cfiscsi_data_wait *cdw, *tmpcdw;
        struct cfiscsi_session *cs, *tcs;
        struct cfiscsi_softc *softc;
        int cold_reset = 0;

        request = PRIV_REQUEST(io);
        cs = PDU_SESSION(request);
        bhstmr = (struct iscsi_bhs_task_management_request *)request->ip_bhs;
        KASSERT((bhstmr->bhstmr_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) ==
            ISCSI_BHS_OPCODE_TASK_REQUEST,
            ("replying to wrong opcode 0x%x", bhstmr->bhstmr_opcode));

#if 0
        CFISCSI_SESSION_DEBUG(cs, "initiator task tag 0x%x; referenced task tag 0x%x",
            bhstmr->bhstmr_initiator_task_tag,
            bhstmr->bhstmr_referenced_task_tag);
#endif

        if ((bhstmr->bhstmr_function & ~0x80) ==
            BHSTMR_FUNCTION_ABORT_TASK) {
                /*
                 * Make sure we no longer wait for Data-Out for this command.
                 */
                CFISCSI_SESSION_LOCK(cs);
                TAILQ_FOREACH_SAFE(cdw,
                    &cs->cs_waiting_for_data_out, cdw_next, tmpcdw) {
                        if (bhstmr->bhstmr_referenced_task_tag !=
                            cdw->cdw_initiator_task_tag)
                                continue;

#if 0
                        CFISCSI_SESSION_DEBUG(cs, "removing csw for initiator task "
                            "tag 0x%x", bhstmr->bhstmr_initiator_task_tag);
#endif
                        TAILQ_REMOVE(&cs->cs_waiting_for_data_out,
                            cdw, cdw_next);
                        cfiscsi_data_wait_abort(cs, cdw, 43);
                }
                CFISCSI_SESSION_UNLOCK(cs);
        }
        if ((bhstmr->bhstmr_function & ~0x80) ==
            BHSTMR_FUNCTION_TARGET_COLD_RESET &&
            io->io_hdr.status == CTL_SUCCESS)
                cold_reset = 1;

        response = cfiscsi_pdu_new_response(request, M_WAITOK);
        bhstmr2 = (struct iscsi_bhs_task_management_response *)
            response->ip_bhs;
        bhstmr2->bhstmr_opcode = ISCSI_BHS_OPCODE_TASK_RESPONSE;
        bhstmr2->bhstmr_flags = 0x80;
        switch (io->taskio.task_status) {
        case CTL_TASK_FUNCTION_COMPLETE:
                bhstmr2->bhstmr_response = BHSTMR_RESPONSE_FUNCTION_COMPLETE;
                break;
        case CTL_TASK_FUNCTION_SUCCEEDED:
                bhstmr2->bhstmr_response = BHSTMR_RESPONSE_FUNCTION_SUCCEEDED;
                break;
        case CTL_TASK_LUN_DOES_NOT_EXIST:
                bhstmr2->bhstmr_response = BHSTMR_RESPONSE_LUN_DOES_NOT_EXIST;
                break;
        case CTL_TASK_FUNCTION_NOT_SUPPORTED:
        default:
                bhstmr2->bhstmr_response = BHSTMR_RESPONSE_FUNCTION_NOT_SUPPORTED;
                break;
        }
        memcpy(bhstmr2->bhstmr_additional_reponse_information,
            io->taskio.task_resp, sizeof(io->taskio.task_resp));
        bhstmr2->bhstmr_initiator_task_tag = bhstmr->bhstmr_initiator_task_tag;

        ctl_free_io(io);
        icl_pdu_free(request);
        cfiscsi_pdu_queue(response);

        if (cold_reset) {
                softc = cs->cs_target->ct_softc;
                mtx_lock(&softc->lock);
                TAILQ_FOREACH(tcs, &softc->sessions, cs_next) {
                        if (tcs->cs_target == cs->cs_target)
                                cfiscsi_session_terminate(tcs);
                }
                mtx_unlock(&softc->lock);
        }
}

static void
cfiscsi_done(union ctl_io *io)
{
        struct icl_pdu *request;
        struct cfiscsi_session *cs;

        KASSERT(((io->io_hdr.status & CTL_STATUS_MASK) != CTL_STATUS_NONE),
                ("invalid CTL status %#x", io->io_hdr.status));

        request = PRIV_REQUEST(io);
        cs = PDU_SESSION(request);

        switch (request->ip_bhs->bhs_opcode & ~ISCSI_BHS_OPCODE_IMMEDIATE) {
        case ISCSI_BHS_OPCODE_SCSI_COMMAND:
                cfiscsi_scsi_command_done(io);
                break;
        case ISCSI_BHS_OPCODE_TASK_REQUEST:
                cfiscsi_task_management_done(io);
                break;
        case ISCSI_BHS_OPCODE_INTERNAL:
                /*
                 * Implicit task termination has just completed; nothing to do.
                 */
                icl_pdu_free(request);
                cs->cs_tasks_aborted = true;
                refcount_release(&cs->cs_outstanding_ctl_pdus);
                wakeup(__DEVOLATILE(void *, &cs->cs_outstanding_ctl_pdus));
                ctl_free_io(io);
                return;
        default:
                panic("cfiscsi_done called with wrong opcode 0x%x",
                    request->ip_bhs->bhs_opcode);
        }

        refcount_release(&cs->cs_outstanding_ctl_pdus);
}