FreeBSD/Linux Kernel Cross Reference
sys/dev/iscsi/iscsi.c

     /*-
      * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      *
      * Copyright (c) 2012 The FreeBSD Foundation
      *
      * This software was developed by Edward Tomasz Napierala under sponsorship
      * from the FreeBSD Foundation.
      *
      * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/bio.h>
    #include <sys/condvar.h>
    #include <sys/conf.h>
    #include <sys/endian.h>
    #include <sys/eventhandler.h>
    #include <sys/file.h>
    #include <sys/kernel.h>
    #include <sys/kthread.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/mbuf.h>
    #include <sys/mutex.h>
    #include <sys/module.h>
    #include <sys/socket.h>
    #include <sys/sockopt.h>
    #include <sys/sysctl.h>
    #include <sys/systm.h>
    #include <sys/sx.h>
    #include <vm/uma.h>
    
    #include <cam/cam.h>
    #include <cam/cam_ccb.h>
    #include <cam/cam_xpt.h>
    #include <cam/cam_debug.h>
    #include <cam/cam_sim.h>
    #include <cam/cam_xpt_sim.h>
    #include <cam/cam_xpt_periph.h>
    #include <cam/cam_periph.h>
    #include <cam/scsi/scsi_all.h>
    #include <cam/scsi/scsi_message.h>
    
    #include <dev/iscsi/icl.h>
    #include <dev/iscsi/icl_wrappers.h>
    #include <dev/iscsi/iscsi_ioctl.h>
    #include <dev/iscsi/iscsi_proto.h>
    #include <dev/iscsi/iscsi.h>
    
    #ifdef ICL_KERNEL_PROXY
    #include <sys/socketvar.h>
    #endif
    
    #ifdef ICL_KERNEL_PROXY
    FEATURE(iscsi_kernel_proxy, "iSCSI initiator built with ICL_KERNEL_PROXY");
    #endif
    
    #ifdef COMPAT_FREEBSD13
    struct iscsi_daemon_request13 {
            unsigned int                    idr_session_id;
            struct iscsi_session_conf       idr_conf;
            uint8_t                         idr_isid[6];
            uint16_t                        idr_tsih;
            uint16_t                        idr_spare_cid;
            struct iscsi_session_limits     idr_limits;
            int                             idr_spare[4];
    };
    
    #define ISCSIDWAIT13    _IOR('I', 0x01, struct iscsi_daemon_request13)
    #endif
    
    /*
     * XXX: This is global so the iscsi_unload() can access it.
     *      Think about how to do this properly.
     */
    static struct iscsi_softc       *sc;
   
   SYSCTL_NODE(_kern, OID_AUTO, iscsi, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
       "iSCSI initiator");
   static int debug = 1;
   SYSCTL_INT(_kern_iscsi, OID_AUTO, debug, CTLFLAG_RWTUN,
       &debug, 0, "Enable debug messages");
   
   static int ping_timeout = 5;
   SYSCTL_INT(_kern_iscsi, OID_AUTO, ping_timeout, CTLFLAG_RWTUN, &ping_timeout,
       0, "Timeout for ping (NOP-Out) requests, in seconds");
   static int iscsid_timeout = 60;
   SYSCTL_INT(_kern_iscsi, OID_AUTO, iscsid_timeout, CTLFLAG_RWTUN, &iscsid_timeout,
       0, "Time to wait for iscsid(8) to handle reconnection, in seconds");
   static int login_timeout = 60;
   SYSCTL_INT(_kern_iscsi, OID_AUTO, login_timeout, CTLFLAG_RWTUN, &login_timeout,
       0, "Time to wait for iscsid(8) to finish Login Phase, in seconds");
   static int maxtags = 255;
   SYSCTL_INT(_kern_iscsi, OID_AUTO, maxtags, CTLFLAG_RWTUN, &maxtags,
       0, "Max number of IO requests queued");
   static int fail_on_disconnection = 0;
   SYSCTL_INT(_kern_iscsi, OID_AUTO, fail_on_disconnection, CTLFLAG_RWTUN,
       &fail_on_disconnection, 0, "Destroy CAM SIM on connection failure");
   static int fail_on_shutdown = 1;
   SYSCTL_INT(_kern_iscsi, OID_AUTO, fail_on_shutdown, CTLFLAG_RWTUN,
       &fail_on_shutdown, 0, "Fail disconnected sessions on shutdown");
   
   static MALLOC_DEFINE(M_ISCSI, "iSCSI", "iSCSI initiator");
   static uma_zone_t iscsi_outstanding_zone;
   
   #define CONN_SESSION(X) ((struct iscsi_session *)X->ic_prv0)
   #define PDU_SESSION(X)  (CONN_SESSION(X->ip_conn))
   
   #define ISCSI_DEBUG(X, ...)                                             \
           do {                                                            \
                   if (debug > 1)                                          \
                           printf("%s: " X "\n", __func__, ## __VA_ARGS__);\
           } while (0)
   
   #define ISCSI_WARN(X, ...)                                              \
           do {                                                            \
                   if (debug > 0) {                                        \
                           printf("WARNING: %s: " X "\n",                  \
                               __func__, ## __VA_ARGS__);                  \
                   }                                                       \
           } while (0)
   
   #define ISCSI_SESSION_DEBUG(S, X, ...)                                  \
           do {                                                            \
                   if (debug > 1) {                                        \
                           printf("%s: %s (%s): " X "\n",                  \
                               __func__, S->is_conf.isc_target_addr,       \
                               S->is_conf.isc_target, ## __VA_ARGS__);     \
                   }                                                       \
           } while (0)
   
   #define ISCSI_SESSION_WARN(S, X, ...)                                   \
           do {                                                            \
                   if (debug > 0) {                                        \
                           printf("WARNING: %s (%s): " X "\n",             \
                               S->is_conf.isc_target_addr,                 \
                               S->is_conf.isc_target, ## __VA_ARGS__);     \
                   }                                                       \
           } while (0)
   
   #define ISCSI_SESSION_LOCK(X)           mtx_lock(&X->is_lock)
   #define ISCSI_SESSION_UNLOCK(X)         mtx_unlock(&X->is_lock)
   #define ISCSI_SESSION_LOCK_ASSERT(X)    mtx_assert(&X->is_lock, MA_OWNED)
   #define ISCSI_SESSION_LOCK_ASSERT_NOT(X) mtx_assert(&X->is_lock, MA_NOTOWNED)
   
   static int      iscsi_ioctl(struct cdev *dev, u_long cmd, caddr_t arg,
                       int mode, struct thread *td);
   
   static struct cdevsw iscsi_cdevsw = {
        .d_version = D_VERSION,
        .d_ioctl   = iscsi_ioctl,
        .d_name    = "iscsi",
   };
   
   static void     iscsi_pdu_queue_locked(struct icl_pdu *request);
   static void     iscsi_pdu_queue(struct icl_pdu *request);
   static void     iscsi_pdu_update_statsn(const struct icl_pdu *response);
   static void     iscsi_pdu_handle_nop_in(struct icl_pdu *response);
   static void     iscsi_pdu_handle_scsi_response(struct icl_pdu *response);
   static void     iscsi_pdu_handle_task_response(struct icl_pdu *response);
   static void     iscsi_pdu_handle_data_in(struct icl_pdu *response);
   static void     iscsi_pdu_handle_logout_response(struct icl_pdu *response);
   static void     iscsi_pdu_handle_r2t(struct icl_pdu *response);
   static void     iscsi_pdu_handle_async_message(struct icl_pdu *response);
   static void     iscsi_pdu_handle_reject(struct icl_pdu *response);
   static void     iscsi_session_reconnect(struct iscsi_session *is);
   static void     iscsi_session_terminate(struct iscsi_session *is);
   static void     iscsi_action(struct cam_sim *sim, union ccb *ccb);
   static struct iscsi_outstanding *iscsi_outstanding_find(struct iscsi_session *is,
                       uint32_t initiator_task_tag);
   static struct iscsi_outstanding *iscsi_outstanding_add(struct iscsi_session *is,
                       struct icl_pdu *request, union ccb *ccb,
                       uint32_t *initiator_task_tagp);
   static void     iscsi_outstanding_remove(struct iscsi_session *is,
                       struct iscsi_outstanding *io);
   
   static bool
   iscsi_pdu_prepare(struct icl_pdu *request)
   {
           struct iscsi_session *is;
           struct iscsi_bhs_scsi_command *bhssc;
   
           is = PDU_SESSION(request);
   
           ISCSI_SESSION_LOCK_ASSERT(is);
   
           /*
            * We're only using fields common for all the request
            * (initiator -> target) PDUs.
            */
           bhssc = (struct iscsi_bhs_scsi_command *)request->ip_bhs;
   
           /*
            * Data-Out PDU does not contain CmdSN.
            */
           if (bhssc->bhssc_opcode != ISCSI_BHS_OPCODE_SCSI_DATA_OUT) {
                   if (ISCSI_SNGT(is->is_cmdsn, is->is_maxcmdsn) &&
                       (bhssc->bhssc_opcode & ISCSI_BHS_OPCODE_IMMEDIATE) == 0) {
                           /*
                            * Current MaxCmdSN prevents us from sending any more
                            * SCSI Command PDUs to the target; postpone the PDU.
                            * It will get resent by either iscsi_pdu_queue(),
                            * or by maintenance thread.
                            */
   #if 0
                           ISCSI_SESSION_DEBUG(is, "postponing send, CmdSN %u, "
                               "ExpCmdSN %u, MaxCmdSN %u, opcode 0x%x",
                               is->is_cmdsn, is->is_expcmdsn, is->is_maxcmdsn,
                               bhssc->bhssc_opcode);
   #endif
                           return (true);
                   }
                   bhssc->bhssc_cmdsn = htonl(is->is_cmdsn);
                   if ((bhssc->bhssc_opcode & ISCSI_BHS_OPCODE_IMMEDIATE) == 0)
                           is->is_cmdsn++;
           }
           bhssc->bhssc_expstatsn = htonl(is->is_statsn + 1);
   
           return (false);
   }
   
   static void
   iscsi_session_send_postponed(struct iscsi_session *is)
   {
           struct icl_pdu *request;
           bool postpone;
   
           ISCSI_SESSION_LOCK_ASSERT(is);
   
           if (STAILQ_EMPTY(&is->is_postponed))
                   return;
           while ((request = STAILQ_FIRST(&is->is_postponed)) != NULL) {
                   postpone = iscsi_pdu_prepare(request);
                   if (postpone)
                           return;
                   STAILQ_REMOVE_HEAD(&is->is_postponed, ip_next);
                   icl_pdu_queue(request);
           }
           xpt_release_simq(is->is_sim, 1);
   }
   
   static void
   iscsi_pdu_queue_locked(struct icl_pdu *request)
   {
           struct iscsi_session *is;
           bool postpone;
   
           is = PDU_SESSION(request);
           ISCSI_SESSION_LOCK_ASSERT(is);
           iscsi_session_send_postponed(is);
           postpone = iscsi_pdu_prepare(request);
           if (postpone) {
                   if (STAILQ_EMPTY(&is->is_postponed))
                           xpt_freeze_simq(is->is_sim, 1);
                   STAILQ_INSERT_TAIL(&is->is_postponed, request, ip_next);
                   return;
           }
           icl_pdu_queue(request);
   }
   
   static void
   iscsi_pdu_queue(struct icl_pdu *request)
   {
           struct iscsi_session *is;
   
           is = PDU_SESSION(request);
           ISCSI_SESSION_LOCK(is);
           iscsi_pdu_queue_locked(request);
           ISCSI_SESSION_UNLOCK(is);
   }
   
   static void
   iscsi_session_logout(struct iscsi_session *is)
   {
           struct icl_pdu *request;
           struct iscsi_bhs_logout_request *bhslr;
   
           request = icl_pdu_new(is->is_conn, M_NOWAIT);
           if (request == NULL)
                   return;
   
           bhslr = (struct iscsi_bhs_logout_request *)request->ip_bhs;
           bhslr->bhslr_opcode = ISCSI_BHS_OPCODE_LOGOUT_REQUEST;
           bhslr->bhslr_reason = BHSLR_REASON_CLOSE_SESSION;
           iscsi_pdu_queue_locked(request);
   }
   
   static void
   iscsi_session_terminate_task(struct iscsi_session *is,
       struct iscsi_outstanding *io, cam_status status)
   {
   
           ISCSI_SESSION_LOCK_ASSERT(is);
   
           if (io->io_ccb != NULL) {
                   io->io_ccb->ccb_h.status &= ~(CAM_SIM_QUEUED | CAM_STATUS_MASK);
                   io->io_ccb->ccb_h.status |= status;
                   if ((io->io_ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                           io->io_ccb->ccb_h.status |= CAM_DEV_QFRZN;
                           xpt_freeze_devq(io->io_ccb->ccb_h.path, 1);
                           ISCSI_SESSION_DEBUG(is, "freezing devq");
                   }
                   xpt_done(io->io_ccb);
           }
           iscsi_outstanding_remove(is, io);
   }
   
   static void
   iscsi_session_terminate_tasks(struct iscsi_session *is, cam_status status)
   {
           struct iscsi_outstanding *io, *tmp;
   
           ISCSI_SESSION_LOCK_ASSERT(is);
   
           TAILQ_FOREACH_SAFE(io, &is->is_outstanding, io_next, tmp) {
                   iscsi_session_terminate_task(is, io, status);
           }
   }
   
   static void
   iscsi_session_cleanup(struct iscsi_session *is, bool destroy_sim)
   {
           struct icl_pdu *pdu;
   
           ISCSI_SESSION_LOCK_ASSERT(is);
   
           /*
            * Don't queue any new PDUs.
            */
           if (is->is_sim != NULL && is->is_simq_frozen == false) {
                   ISCSI_SESSION_DEBUG(is, "freezing");
                   xpt_freeze_simq(is->is_sim, 1);
                   is->is_simq_frozen = true;
           }
   
           /*
            * Remove postponed PDUs.
            */
           if (!STAILQ_EMPTY(&is->is_postponed))
                   xpt_release_simq(is->is_sim, 1);
           while ((pdu = STAILQ_FIRST(&is->is_postponed)) != NULL) {
                   STAILQ_REMOVE_HEAD(&is->is_postponed, ip_next);
                   icl_pdu_free(pdu);
           }
   
           if (destroy_sim == false) {
                   /*
                    * Terminate SCSI tasks, asking CAM to requeue them.
                    */
                   iscsi_session_terminate_tasks(is, CAM_REQUEUE_REQ);
                   return;
           }
   
           iscsi_session_terminate_tasks(is, CAM_DEV_NOT_THERE);
   
           if (is->is_sim == NULL)
                   return;
   
           ISCSI_SESSION_DEBUG(is, "deregistering SIM");
           xpt_async(AC_LOST_DEVICE, is->is_path, NULL);
   
           if (is->is_simq_frozen) {
                   is->is_simq_frozen = false;
                   xpt_release_simq(is->is_sim, 1);
           }
   
           xpt_free_path(is->is_path);
           is->is_path = NULL;
           xpt_bus_deregister(cam_sim_path(is->is_sim));
           cam_sim_free(is->is_sim, TRUE /*free_devq*/);
           is->is_sim = NULL;
           is->is_devq = NULL;
   }
   
   static void
   iscsi_maintenance_thread_reconnect(struct iscsi_session *is)
   {
           /*
            * As we will be reconnecting shortly,
            * discard outstanding data immediately on
            * close(), also notify peer via RST if
            * any packets come in.
            */
           struct socket *so;
           so = is->is_conn->ic_socket;
           if (so != NULL) {
                   struct sockopt sopt;
                   struct linger sl;
                   sopt.sopt_dir     = SOPT_SET;
                   sopt.sopt_level   = SOL_SOCKET;
                   sopt.sopt_name    = SO_LINGER;
                   sopt.sopt_val     = &sl;
                   sopt.sopt_valsize = sizeof(sl);
                   sl.l_onoff        = 1;  /* non-zero value enables linger option in kernel */
                   sl.l_linger       = 0;  /* timeout interval in seconds */
                   sosetopt(is->is_conn->ic_socket, &sopt);
           }
   
           icl_conn_close(is->is_conn);
   
           ISCSI_SESSION_LOCK(is);
   
           is->is_connected = false;
           is->is_reconnecting = false;
           is->is_login_phase = false;
   
   #ifdef ICL_KERNEL_PROXY
           if (is->is_login_pdu != NULL) {
                   icl_pdu_free(is->is_login_pdu);
                   is->is_login_pdu = NULL;
           }
           cv_signal(&is->is_login_cv);
   #endif
   
           if (fail_on_disconnection) {
                   ISCSI_SESSION_DEBUG(is, "connection failed, destroying devices");
                   iscsi_session_cleanup(is, true);
           } else {
                   iscsi_session_cleanup(is, false);
           }
   
           KASSERT(TAILQ_EMPTY(&is->is_outstanding),
               ("destroying session with active tasks"));
           KASSERT(STAILQ_EMPTY(&is->is_postponed),
               ("destroying session with postponed PDUs"));
   
           if (is->is_conf.isc_enable == 0 && is->is_conf.isc_discovery == 0) {
                   ISCSI_SESSION_UNLOCK(is);
                   return;
           }
   
           /*
            * Request immediate reconnection from iscsid(8).
            */
           //ISCSI_SESSION_DEBUG(is, "waking up iscsid(8)");
           is->is_waiting_for_iscsid = true;
           strlcpy(is->is_reason, "Waiting for iscsid(8)", sizeof(is->is_reason));
           is->is_timeout = 0;
           ISCSI_SESSION_UNLOCK(is);
           cv_signal(&is->is_softc->sc_cv);
   }
   
   static void
   iscsi_maintenance_thread_terminate(struct iscsi_session *is)
   {
           struct iscsi_softc *sc;
   
           sc = is->is_softc;
           sx_xlock(&sc->sc_lock);
           TAILQ_REMOVE(&sc->sc_sessions, is, is_next);
           sx_xunlock(&sc->sc_lock);
   
           icl_conn_close(is->is_conn);
           callout_drain(&is->is_callout);
   
           ISCSI_SESSION_LOCK(is);
   
           KASSERT(is->is_terminating, ("is_terminating == false"));
   
   #ifdef ICL_KERNEL_PROXY
           if (is->is_login_pdu != NULL) {
                   icl_pdu_free(is->is_login_pdu);
                   is->is_login_pdu = NULL;
           }
           cv_signal(&is->is_login_cv);
   #endif
   
           iscsi_session_cleanup(is, true);
   
           KASSERT(TAILQ_EMPTY(&is->is_outstanding),
               ("destroying session with active tasks"));
           KASSERT(STAILQ_EMPTY(&is->is_postponed),
               ("destroying session with postponed PDUs"));
   
           ISCSI_SESSION_UNLOCK(is);
   
           icl_conn_free(is->is_conn);
           mtx_destroy(&is->is_lock);
           cv_destroy(&is->is_maintenance_cv);
   #ifdef ICL_KERNEL_PROXY
           cv_destroy(&is->is_login_cv);
   #endif
   
           ISCSI_SESSION_DEBUG(is, "terminated");
           free(is, M_ISCSI);
   
           /*
            * The iscsi_unload() routine might be waiting.
            */
           cv_signal(&sc->sc_cv);
   }
   
   static void
   iscsi_maintenance_thread(void *arg)
   {
           struct iscsi_session *is = arg;
   
           ISCSI_SESSION_LOCK(is);
           for (;;) {
                   if (is->is_reconnecting == false &&
                       is->is_terminating == false &&
                       (STAILQ_EMPTY(&is->is_postponed) ||
                        ISCSI_SNGT(is->is_cmdsn, is->is_maxcmdsn)))
                           cv_wait(&is->is_maintenance_cv, &is->is_lock);
   
                   /* Terminate supersedes reconnect. */
                   if (is->is_terminating) {
                           ISCSI_SESSION_UNLOCK(is);
                           iscsi_maintenance_thread_terminate(is);
                           kthread_exit();
                           return;
                   }
   
                   if (is->is_reconnecting) {
                           ISCSI_SESSION_UNLOCK(is);
                           iscsi_maintenance_thread_reconnect(is);
                           ISCSI_SESSION_LOCK(is);
                           continue;
                   }
   
                   iscsi_session_send_postponed(is);
           }
           ISCSI_SESSION_UNLOCK(is);
   }
   
   static void
   iscsi_session_reconnect(struct iscsi_session *is)
   {
   
           /*
            * XXX: We can't use locking here, because
            *      it's being called from various contexts.
            *      Hope it doesn't break anything.
            */
           if (is->is_reconnecting)
                   return;
   
           is->is_reconnecting = true;
           cv_signal(&is->is_maintenance_cv);
   }
   
   static void
   iscsi_session_terminate(struct iscsi_session *is)
   {
   
           if (is->is_terminating)
                   return;
   
           is->is_terminating = true;
   
   #if 0
           iscsi_session_logout(is);
   #endif
           cv_signal(&is->is_maintenance_cv);
   }
   
   static void
   iscsi_callout(void *context)
   {
           struct icl_pdu *request;
           struct iscsi_bhs_nop_out *bhsno;
           struct iscsi_session *is;
           bool reconnect_needed = false;
           sbintime_t sbt, pr;
   
           is = context;
   
           ISCSI_SESSION_LOCK(is);
           if (is->is_terminating) {
                   ISCSI_SESSION_UNLOCK(is);
                   return;
           }
   
           sbt = mstosbt(995);
           pr  = mstosbt(10);
           callout_schedule_sbt(&is->is_callout, sbt, pr, 0);
   
           if (is->is_conf.isc_enable == 0)
                   goto out;
   
           is->is_timeout++;
   
           if (is->is_waiting_for_iscsid) {
                   if (iscsid_timeout > 0 && is->is_timeout > iscsid_timeout) {
                           ISCSI_SESSION_WARN(is, "timed out waiting for iscsid(8) "
                               "for %d seconds; reconnecting",
                               is->is_timeout);
                           reconnect_needed = true;
                   }
                   goto out;
           }
   
           if (is->is_login_phase) {
                   if (is->is_login_timeout > 0 && is->is_timeout > is->is_login_timeout) {
                           ISCSI_SESSION_WARN(is, "login timed out after %d seconds; "
                               "reconnecting", is->is_timeout);
                           reconnect_needed = true;
                   }
                   goto out;
           }
   
           if (is->is_ping_timeout <= 0) {
                   /*
                    * Pings are disabled.  Don't send NOP-Out in this case.
                    * Reset the timeout, to avoid triggering reconnection,
                    * should the user decide to reenable them.
                    */
                   is->is_timeout = 0;
                   goto out;
           }
   
           if (is->is_timeout >= is->is_ping_timeout) {
                   ISCSI_SESSION_WARN(is, "no ping reply (NOP-In) after %d seconds; "
                       "reconnecting", is->is_ping_timeout);
                   reconnect_needed = true;
                   goto out;
           }
   
           ISCSI_SESSION_UNLOCK(is);
   
           /*
            * 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 (is->is_timeout < 2)
                   return;
   
           request = icl_pdu_new(is->is_conn, M_NOWAIT);
           if (request == NULL) {
                   ISCSI_SESSION_WARN(is, "failed to allocate PDU");
                   return;
           }
           bhsno = (struct iscsi_bhs_nop_out *)request->ip_bhs;
           bhsno->bhsno_opcode = ISCSI_BHS_OPCODE_NOP_OUT |
               ISCSI_BHS_OPCODE_IMMEDIATE;
           bhsno->bhsno_flags = 0x80;
           bhsno->bhsno_target_transfer_tag = 0xffffffff;
           iscsi_pdu_queue(request);
           return;
   
   out:
           if (is->is_terminating) {
                   ISCSI_SESSION_UNLOCK(is);
                   return;
           }
   
           ISCSI_SESSION_UNLOCK(is);
   
           if (reconnect_needed)
                   iscsi_session_reconnect(is);
   }
   
   static void
   iscsi_pdu_update_statsn(const struct icl_pdu *response)
   {
           const struct iscsi_bhs_data_in *bhsdi;
           struct iscsi_session *is;
           uint32_t expcmdsn, maxcmdsn, statsn;
   
           is = PDU_SESSION(response);
   
           ISCSI_SESSION_LOCK_ASSERT(is);
   
           /*
            * We're only using fields common for all the response
            * (target -> initiator) PDUs.
            */
           bhsdi = (const struct iscsi_bhs_data_in *)response->ip_bhs;
           /*
            * Ok, I lied.  In case of Data-In, "The fields StatSN, Status,
            * and Residual Count only have meaningful content if the S bit
            * is set to 1", so we also need to check the bit specific for
            * Data-In PDU.
            */
           if (bhsdi->bhsdi_opcode != ISCSI_BHS_OPCODE_SCSI_DATA_IN ||
               (bhsdi->bhsdi_flags & BHSDI_FLAGS_S) != 0) {
                   statsn = ntohl(bhsdi->bhsdi_statsn);
                   if (statsn != is->is_statsn && statsn != (is->is_statsn + 1)) {
                           /* XXX: This is normal situation for MCS */
                           ISCSI_SESSION_WARN(is, "PDU 0x%x StatSN %u != "
                               "session ExpStatSN %u (or + 1); reconnecting",
                               bhsdi->bhsdi_opcode, statsn, is->is_statsn);
                           iscsi_session_reconnect(is);
                   }
                   if (ISCSI_SNGT(statsn, is->is_statsn))
                           is->is_statsn = statsn;
           }
   
           expcmdsn = ntohl(bhsdi->bhsdi_expcmdsn);
           maxcmdsn = ntohl(bhsdi->bhsdi_maxcmdsn);
   
           if (ISCSI_SNLT(maxcmdsn + 1, expcmdsn)) {
                   ISCSI_SESSION_DEBUG(is,
                       "PDU MaxCmdSN %u + 1 < PDU ExpCmdSN %u; ignoring",
                       maxcmdsn, expcmdsn);
           } else {
                   if (ISCSI_SNGT(maxcmdsn, is->is_maxcmdsn)) {
                           is->is_maxcmdsn = maxcmdsn;
   
                           /*
                            * Command window increased; kick the maintanance thread
                            * to send out postponed commands.
                            */
                           if (!STAILQ_EMPTY(&is->is_postponed))
                                   cv_signal(&is->is_maintenance_cv);
                   } else if (ISCSI_SNLT(maxcmdsn, is->is_maxcmdsn)) {
                           /* XXX: This is normal situation for MCS */
                           ISCSI_SESSION_DEBUG(is,
                               "PDU MaxCmdSN %u < session MaxCmdSN %u; ignoring",
                               maxcmdsn, is->is_maxcmdsn);
                   }
   
                   if (ISCSI_SNGT(expcmdsn, is->is_expcmdsn)) {
                           is->is_expcmdsn = expcmdsn;
                   } else if (ISCSI_SNLT(expcmdsn, is->is_expcmdsn)) {
                           /* XXX: This is normal situation for MCS */
                           ISCSI_SESSION_DEBUG(is,
                               "PDU ExpCmdSN %u < session ExpCmdSN %u; ignoring",
                               expcmdsn, is->is_expcmdsn);
                   }
           }
   
           /*
            * Every incoming PDU - not just NOP-In - 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.
            */
           is->is_timeout = 0;
   }
   
   static void
   iscsi_receive_callback(struct icl_pdu *response)
   {
           struct iscsi_session *is;
   
           is = PDU_SESSION(response);
   
           ISCSI_SESSION_LOCK(is);
   
           iscsi_pdu_update_statsn(response);
   
   #ifdef ICL_KERNEL_PROXY
           if (is->is_login_phase) {
                   if (is->is_login_pdu == NULL)
                           is->is_login_pdu = response;
                   else
                           icl_pdu_free(response);
                   ISCSI_SESSION_UNLOCK(is);
                   cv_signal(&is->is_login_cv);
                   return;
           }
   #endif
   
           /*
            * The handling routine is responsible for freeing the PDU
            * when it's no longer needed.
            */
           switch (response->ip_bhs->bhs_opcode) {
           case ISCSI_BHS_OPCODE_NOP_IN:
                   iscsi_pdu_handle_nop_in(response);
                   ISCSI_SESSION_UNLOCK(is);
                   break;
           case ISCSI_BHS_OPCODE_SCSI_RESPONSE:
                   iscsi_pdu_handle_scsi_response(response);
                   /* Session lock dropped inside. */
                   ISCSI_SESSION_LOCK_ASSERT_NOT(is);
                   break;
           case ISCSI_BHS_OPCODE_TASK_RESPONSE:
                   iscsi_pdu_handle_task_response(response);
                   ISCSI_SESSION_UNLOCK(is);
                   break;
           case ISCSI_BHS_OPCODE_SCSI_DATA_IN:
                   iscsi_pdu_handle_data_in(response);
                   /* Session lock dropped inside. */
                   ISCSI_SESSION_LOCK_ASSERT_NOT(is);
                   break;
           case ISCSI_BHS_OPCODE_LOGOUT_RESPONSE:
                   iscsi_pdu_handle_logout_response(response);
                   ISCSI_SESSION_UNLOCK(is);
                   break;
           case ISCSI_BHS_OPCODE_R2T:
                   iscsi_pdu_handle_r2t(response);
                   ISCSI_SESSION_UNLOCK(is);
                   break;
           case ISCSI_BHS_OPCODE_ASYNC_MESSAGE:
                   iscsi_pdu_handle_async_message(response);
                   ISCSI_SESSION_UNLOCK(is);
                   break;
           case ISCSI_BHS_OPCODE_REJECT:
                   iscsi_pdu_handle_reject(response);
                   ISCSI_SESSION_UNLOCK(is);
                   break;
           default:
                   ISCSI_SESSION_WARN(is, "received PDU with unsupported "
                       "opcode 0x%x; reconnecting",
                       response->ip_bhs->bhs_opcode);
                   iscsi_session_reconnect(is);
                   ISCSI_SESSION_UNLOCK(is);
                   icl_pdu_free(response);
           }
   }
   
   static void
   iscsi_error_callback(struct icl_conn *ic)
   {
           struct iscsi_session *is;
   
           is = CONN_SESSION(ic);
   
           ISCSI_SESSION_WARN(is, "connection error; reconnecting");
           iscsi_session_reconnect(is);
   }
   
   static void
   iscsi_pdu_handle_nop_in(struct icl_pdu *response)
   {
           struct iscsi_session *is;
           struct iscsi_bhs_nop_out *bhsno;
           struct iscsi_bhs_nop_in *bhsni;
           struct icl_pdu *request;
           void *data = NULL;
           size_t datasize;
           int error;
   
           is = PDU_SESSION(response);
           bhsni = (struct iscsi_bhs_nop_in *)response->ip_bhs;
   
           if (bhsni->bhsni_target_transfer_tag == 0xffffffff) {
                   /*
                    * Nothing to do; iscsi_pdu_update_statsn() already
                    * zeroed the timeout.
                    */
                   icl_pdu_free(response);
                   return;
           }
   
           datasize = icl_pdu_data_segment_length(response);
           if (datasize > 0) {
                   data = malloc(datasize, M_ISCSI, M_NOWAIT | M_ZERO);
                   if (data == NULL) {
                           ISCSI_SESSION_WARN(is, "failed to allocate memory; "
                               "reconnecting");
                           icl_pdu_free(response);
                           iscsi_session_reconnect(is);
                           return;
                   }
                   icl_pdu_get_data(response, 0, data, datasize);
           }
   
           request = icl_pdu_new(response->ip_conn, M_NOWAIT);
           if (request == NULL) {
                   ISCSI_SESSION_WARN(is, "failed to allocate memory; "
                       "reconnecting");
                   free(data, M_ISCSI);
                   icl_pdu_free(response);
                   iscsi_session_reconnect(is);
                   return;
           }
           bhsno = (struct iscsi_bhs_nop_out *)request->ip_bhs;
           bhsno->bhsno_opcode = ISCSI_BHS_OPCODE_NOP_OUT |
               ISCSI_BHS_OPCODE_IMMEDIATE;
           bhsno->bhsno_flags = 0x80;
           bhsno->bhsno_initiator_task_tag = 0xffffffff;
           bhsno->bhsno_target_transfer_tag = bhsni->bhsni_target_transfer_tag;
           if (datasize > 0) {
                   error = icl_pdu_append_data(request, data, datasize, M_NOWAIT);
                   if (error != 0) {
                           ISCSI_SESSION_WARN(is, "failed to allocate memory; "
                               "reconnecting");
                           free(data, M_ISCSI);
                           icl_pdu_free(request);
                           icl_pdu_free(response);
                           iscsi_session_reconnect(is);
                           return;
                   }
                   free(data, M_ISCSI);
           }
   
           icl_pdu_free(response);
           iscsi_pdu_queue_locked(request);
   }
   
   static void
   iscsi_pdu_handle_scsi_response(struct icl_pdu *response)
   {
           struct iscsi_bhs_scsi_response *bhssr;
           struct iscsi_outstanding *io;
           struct iscsi_session *is;
           union ccb *ccb;
           struct ccb_scsiio *csio;
           size_t data_segment_len, received;
           uint16_t sense_len;
           uint32_t resid;
   
           is = PDU_SESSION(response);
   
           bhssr = (struct iscsi_bhs_scsi_response *)response->ip_bhs;
           io = iscsi_outstanding_find(is, bhssr->bhssr_initiator_task_tag);
           if (io == NULL || io->io_ccb == NULL) {
                   ISCSI_SESSION_WARN(is, "bad itt 0x%x", bhssr->bhssr_initiator_task_tag);
                   icl_pdu_free(response);
                   iscsi_session_reconnect(is);
                   ISCSI_SESSION_UNLOCK(is);
                   return;
           }
   
           ccb = io->io_ccb;
           if (bhssr->bhssr_response == BHSSR_RESPONSE_COMMAND_COMPLETED) {
                   if (ntohl(bhssr->bhssr_expdatasn) != io->io_datasn) {
                           ISCSI_SESSION_WARN(is,
                               "ExpDataSN mismatch in SCSI Response (%u vs %u)",
                               ntohl(bhssr->bhssr_expdatasn), io->io_datasn);
   
                           /*
                            * XXX: Permit an ExpDataSN of zero for errors.
                            *
                            * This doesn't conform to RFC 7143, but some
                            * targets seem to do this.
                            */
                           if (bhssr->bhssr_status != 0 &&
                               bhssr->bhssr_expdatasn == htonl(0))
                                   goto skip_expdatasn;
   
                           icl_pdu_free(response);
                           iscsi_session_reconnect(is);
                           ISCSI_SESSION_UNLOCK(is);
                           return;
                   }
           } else {
                   if (bhssr->bhssr_expdatasn != htonl(0)) {
                           ISCSI_SESSION_WARN(is,
                               "ExpDataSN mismatch in SCSI Response (%u vs 0)",
                               ntohl(bhssr->bhssr_expdatasn));
                           icl_pdu_free(response);
                           iscsi_session_reconnect(is);
                           ISCSI_SESSION_UNLOCK(is);
                           return;
                   }
           }
   skip_expdatasn:
   
           /*
            * With iSER, after getting good response we can be sure
            * that all the data has been successfully transferred.
            */
           if (is->is_conn->ic_iser) {
                   resid = ntohl(bhssr->bhssr_residual_count);
                   if (bhssr->bhssr_flags & BHSSR_FLAGS_RESIDUAL_UNDERFLOW) {
                           io->io_received = ccb->csio.dxfer_len - resid;
                   } else if (bhssr->bhssr_flags & BHSSR_FLAGS_RESIDUAL_OVERFLOW) {
                           ISCSI_SESSION_WARN(is, "overflow: target indicates %d", resid);
                   } else {
                           io->io_received = ccb->csio.dxfer_len;
                   }
           }
   
           received = io->io_received;
           iscsi_outstanding_remove(is, io);
           ISCSI_SESSION_UNLOCK(is);
   
           if (bhssr->bhssr_response != BHSSR_RESPONSE_COMMAND_COMPLETED) {
                   ISCSI_SESSION_WARN(is, "service response 0x%x", bhssr->bhssr_response);
                   if ((ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                           xpt_freeze_devq(ccb->ccb_h.path, 1);
                           ISCSI_SESSION_DEBUG(is, "freezing devq");
                   }
                   ccb->ccb_h.status = CAM_REQ_CMP_ERR | CAM_DEV_QFRZN;
           } else if (bhssr->bhssr_status == 0) {
                   ccb->ccb_h.status = CAM_REQ_CMP;
           } else {
                   if ((ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                          xpt_freeze_devq(ccb->ccb_h.path, 1);
                          ISCSI_SESSION_DEBUG(is, "freezing devq");
                  }
                  ccb->ccb_h.status = CAM_SCSI_STATUS_ERROR | CAM_DEV_QFRZN;
                  ccb->csio.scsi_status = bhssr->bhssr_status;
          }
  
          csio = &ccb->csio;
          data_segment_len = icl_pdu_data_segment_length(response);
          if (data_segment_len > 0) {
                  if (data_segment_len < sizeof(sense_len)) {
                          ISCSI_SESSION_WARN(is, "truncated data segment (%zd bytes)",
                              data_segment_len);
                          if ((ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                                  xpt_freeze_devq(ccb->ccb_h.path, 1);
                                  ISCSI_SESSION_DEBUG(is, "freezing devq");
                          }
                          ccb->ccb_h.status = CAM_REQ_CMP_ERR | CAM_DEV_QFRZN;
                          goto out;
                  }
                  icl_pdu_get_data(response, 0, &sense_len, sizeof(sense_len));
                  sense_len = ntohs(sense_len);
  #if 0
                  ISCSI_SESSION_DEBUG(is, "sense_len %d, data len %zd",
                      sense_len, data_segment_len);
  #endif
                  if (sizeof(sense_len) + sense_len > data_segment_len) {
                          ISCSI_SESSION_WARN(is, "truncated data segment "
                              "(%zd bytes, should be %zd)",
                              data_segment_len, sizeof(sense_len) + sense_len);
                          if ((ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                                  xpt_freeze_devq(ccb->ccb_h.path, 1);
                                  ISCSI_SESSION_DEBUG(is, "freezing devq");
                          }
                          ccb->ccb_h.status = CAM_REQ_CMP_ERR | CAM_DEV_QFRZN;
                          goto out;
                  } else if (sizeof(sense_len) + sense_len < data_segment_len)
                          ISCSI_SESSION_WARN(is, "oversize data segment "
                              "(%zd bytes, should be %zd)",
                              data_segment_len, sizeof(sense_len) + sense_len);
                  if (sense_len > csio->sense_len) {
                          ISCSI_SESSION_DEBUG(is, "truncating sense from %d to %d",
                              sense_len, csio->sense_len);
                          sense_len = csio->sense_len;
                  }
                  icl_pdu_get_data(response, sizeof(sense_len), &csio->sense_data, sense_len);
                  csio->sense_resid = csio->sense_len - sense_len;
                  ccb->ccb_h.status |= CAM_AUTOSNS_VALID;
          }
  
  out:
          if (bhssr->bhssr_flags & BHSSR_FLAGS_RESIDUAL_UNDERFLOW)
                  csio->resid = ntohl(bhssr->bhssr_residual_count);
  
          if ((csio->ccb_h.flags & CAM_DIR_MASK) == CAM_DIR_IN) {
                  KASSERT(received <= csio->dxfer_len,
                      ("received > csio->dxfer_len"));
                  if (received < csio->dxfer_len) {
                          if (csio->resid != csio->dxfer_len - received) {
                                  ISCSI_SESSION_WARN(is, "underflow mismatch: "
                                      "target indicates %d, we calculated %zd",
                                      csio->resid, csio->dxfer_len - received);
                          }
                          csio->resid = csio->dxfer_len - received;
                  }
          }
  
          xpt_done(ccb);
          icl_pdu_free(response);
  }
  
  static void
  iscsi_pdu_handle_task_response(struct icl_pdu *response)
  {
          struct iscsi_bhs_task_management_response *bhstmr;
          struct iscsi_outstanding *io, *aio;
          struct iscsi_session *is;
  
          is = PDU_SESSION(response);
  
          bhstmr = (struct iscsi_bhs_task_management_response *)response->ip_bhs;
          io = iscsi_outstanding_find(is, bhstmr->bhstmr_initiator_task_tag);
          if (io == NULL || io->io_ccb != NULL) {
                  ISCSI_SESSION_WARN(is, "bad itt 0x%x",
                      bhstmr->bhstmr_initiator_task_tag);
                  icl_pdu_free(response);
                  iscsi_session_reconnect(is);
                  return;
          }
  
          if (bhstmr->bhstmr_response != BHSTMR_RESPONSE_FUNCTION_COMPLETE) {
                  ISCSI_SESSION_WARN(is, "task response 0x%x",
                      bhstmr->bhstmr_response);
          } else {
                  aio = iscsi_outstanding_find(is, io->io_referenced_task_tag);
                  if (aio != NULL && aio->io_ccb != NULL)
                          iscsi_session_terminate_task(is, aio, CAM_REQ_ABORTED);
          }
  
          iscsi_outstanding_remove(is, io);
          icl_pdu_free(response);
  }
  
  static void
  iscsi_pdu_get_data_csio(struct icl_pdu *response, size_t pdu_offset,
      struct ccb_scsiio *csio, size_t oreceived, size_t data_segment_len)
  {
          switch (csio->ccb_h.flags & CAM_DATA_MASK) {
          case CAM_DATA_BIO:
                  icl_pdu_get_bio(response, pdu_offset,
                      (struct bio *)csio->data_ptr, oreceived, data_segment_len);
                  break;
          case CAM_DATA_VADDR:
                  icl_pdu_get_data(response, pdu_offset,
                      csio->data_ptr + oreceived, data_segment_len);
                  break;
          default:
                  __assert_unreachable();
          }
  }
  
  static void
  iscsi_pdu_handle_data_in(struct icl_pdu *response)
  {
          struct iscsi_bhs_data_in *bhsdi;
          struct iscsi_outstanding *io;
          struct iscsi_session *is;
          union ccb *ccb;
          struct ccb_scsiio *csio;
          size_t data_segment_len, received, oreceived;
  
          is = PDU_SESSION(response);
          bhsdi = (struct iscsi_bhs_data_in *)response->ip_bhs;
          io = iscsi_outstanding_find(is, bhsdi->bhsdi_initiator_task_tag);
          if (io == NULL || io->io_ccb == NULL) {
                  ISCSI_SESSION_WARN(is, "bad itt 0x%x", bhsdi->bhsdi_initiator_task_tag);
                  icl_pdu_free(response);
                  iscsi_session_reconnect(is);
                  ISCSI_SESSION_UNLOCK(is);
                  return;
          }
  
          if (io->io_datasn != ntohl(bhsdi->bhsdi_datasn)) {
                  ISCSI_SESSION_WARN(is, "received Data-In PDU with "
                      "DataSN %u, while expected %u; dropping connection",
                      ntohl(bhsdi->bhsdi_datasn), io->io_datasn);
                  icl_pdu_free(response);
                  iscsi_session_reconnect(is);
                  ISCSI_SESSION_UNLOCK(is);
                  return;
          }
          io->io_datasn += response->ip_additional_pdus + 1;
  
          data_segment_len = icl_pdu_data_segment_length(response);
          if (data_segment_len == 0) {
                  /*
                   * "The sending of 0 length data segments should be avoided,
                   * but initiators and targets MUST be able to properly receive
                   * 0 length data segments."
                   */
                  ISCSI_SESSION_UNLOCK(is);
                  icl_pdu_free(response);
                  return;
          }
  
          /*
           * We need to track this for security reasons - without it, malicious target
           * could respond to SCSI READ without sending Data-In PDUs, which would result
           * in read operation on the initiator side returning random kernel data.
           */
          if (ntohl(bhsdi->bhsdi_buffer_offset) != io->io_received) {
                  ISCSI_SESSION_WARN(is, "data out of order; expected offset %zd, got %zd",
                      io->io_received, (size_t)ntohl(bhsdi->bhsdi_buffer_offset));
                  icl_pdu_free(response);
                  iscsi_session_reconnect(is);
                  ISCSI_SESSION_UNLOCK(is);
                  return;
          }
  
          ccb = io->io_ccb;
          csio = &ccb->csio;
  
          if (io->io_received + data_segment_len > csio->dxfer_len) {
                  ISCSI_SESSION_WARN(is, "oversize data segment (%zd bytes "
                      "at offset %zd, buffer is %d)",
                      data_segment_len, io->io_received, csio->dxfer_len);
                  icl_pdu_free(response);
                  iscsi_session_reconnect(is);
                  ISCSI_SESSION_UNLOCK(is);
                  return;
          }
  
          oreceived = io->io_received;
          io->io_received += data_segment_len;
          received = io->io_received;
          if ((bhsdi->bhsdi_flags & BHSDI_FLAGS_S) != 0)
                  iscsi_outstanding_remove(is, io);
          ISCSI_SESSION_UNLOCK(is);
  
          iscsi_pdu_get_data_csio(response, 0, csio, oreceived, data_segment_len);
  
          /*
           * XXX: Check F.
           */
          if ((bhsdi->bhsdi_flags & BHSDI_FLAGS_S) == 0) {
                  /*
                   * Nothing more to do.
                   */
                  icl_pdu_free(response);
                  return;
          }
  
          //ISCSI_SESSION_DEBUG(is, "got S flag; status 0x%x", bhsdi->bhsdi_status);
          if (bhsdi->bhsdi_status == 0) {
                  ccb->ccb_h.status = CAM_REQ_CMP;
          } else {
                  if ((ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                          xpt_freeze_devq(ccb->ccb_h.path, 1);
                          ISCSI_SESSION_DEBUG(is, "freezing devq");
                  }
                  ccb->ccb_h.status = CAM_SCSI_STATUS_ERROR | CAM_DEV_QFRZN;
                  csio->scsi_status = bhsdi->bhsdi_status;
          }
  
          if ((csio->ccb_h.flags & CAM_DIR_MASK) == CAM_DIR_IN) {
                  KASSERT(received <= csio->dxfer_len,
                      ("received > csio->dxfer_len"));
                  if (received < csio->dxfer_len) {
                          csio->resid = ntohl(bhsdi->bhsdi_residual_count);
                          if (csio->resid != csio->dxfer_len - received) {
                                  ISCSI_SESSION_WARN(is, "underflow mismatch: "
                                      "target indicates %d, we calculated %zd",
                                      csio->resid, csio->dxfer_len - received);
                          }
                          csio->resid = csio->dxfer_len - received;
                  }
          }
  
          xpt_done(ccb);
          icl_pdu_free(response);
  }
  
  static void
  iscsi_pdu_handle_logout_response(struct icl_pdu *response)
  {
  
          ISCSI_SESSION_DEBUG(PDU_SESSION(response), "logout response");
          icl_pdu_free(response);
  }
  
  static int
  iscsi_pdu_append_data_csio(struct icl_pdu *request, struct ccb_scsiio *csio,
      size_t off, size_t len, int how)
  {
          switch (csio->ccb_h.flags & CAM_DATA_MASK) {
          case CAM_DATA_BIO:
                  return (icl_pdu_append_bio(request,
                          (struct bio *)csio->data_ptr, off, len, how));
          case CAM_DATA_VADDR:
                  return (icl_pdu_append_data(request, csio->data_ptr + off, len,
                      how));
          default:
                  __assert_unreachable();
          }
  }
  
  static void
  iscsi_pdu_handle_r2t(struct icl_pdu *response)
  {
          struct icl_pdu *request;
          struct iscsi_session *is;
          struct iscsi_bhs_r2t *bhsr2t;
          struct iscsi_bhs_data_out *bhsdo;
          struct iscsi_outstanding *io;
          struct ccb_scsiio *csio;
          size_t off, len, max_send_data_segment_length, total_len;
          int error;
          uint32_t datasn = 0;
  
          is = PDU_SESSION(response);
  
          bhsr2t = (struct iscsi_bhs_r2t *)response->ip_bhs;
          io = iscsi_outstanding_find(is, bhsr2t->bhsr2t_initiator_task_tag);
          if (io == NULL || io->io_ccb == NULL) {
                  ISCSI_SESSION_WARN(is, "bad itt 0x%x; reconnecting",
                      bhsr2t->bhsr2t_initiator_task_tag);
                  icl_pdu_free(response);
                  iscsi_session_reconnect(is);
                  return;
          }
  
          csio = &io->io_ccb->csio;
  
          if ((csio->ccb_h.flags & CAM_DIR_MASK) != CAM_DIR_OUT) {
                  ISCSI_SESSION_WARN(is, "received R2T for read command; reconnecting");
                  icl_pdu_free(response);
                  iscsi_session_reconnect(is);
                  return;
          }
  
          /*
           * XXX: Verify R2TSN.
           */
  
          off = ntohl(bhsr2t->bhsr2t_buffer_offset);
          if (off > csio->dxfer_len) {
                  ISCSI_SESSION_WARN(is, "target requested invalid offset "
                      "%zd, buffer is %d; reconnecting", off, csio->dxfer_len);
                  icl_pdu_free(response);
                  iscsi_session_reconnect(is);
                  return;
          }
  
          total_len = ntohl(bhsr2t->bhsr2t_desired_data_transfer_length);
          if (total_len == 0 || total_len > csio->dxfer_len) {
                  ISCSI_SESSION_WARN(is, "target requested invalid length "
                      "%zd, buffer is %d; reconnecting", total_len, csio->dxfer_len);
                  icl_pdu_free(response);
                  iscsi_session_reconnect(is);
                  return;
          }
  
          //ISCSI_SESSION_DEBUG(is, "r2t; off %zd, len %zd", off, total_len);
  
          if (is->is_conn->ic_hw_isomax != 0)
                  max_send_data_segment_length = is->is_conn->ic_hw_isomax;
          else
                  max_send_data_segment_length =
                      is->is_conn->ic_max_send_data_segment_length;
          for (;;) {
                  len = total_len;
  
                  if (len > max_send_data_segment_length)
                          len = max_send_data_segment_length;
  
                  if (off + len > csio->dxfer_len) {
                          ISCSI_SESSION_WARN(is, "target requested invalid "
                              "length/offset %zd, buffer is %d; reconnecting",
                              off + len, csio->dxfer_len);
                          icl_pdu_free(response);
                          iscsi_session_reconnect(is);
                          return;
                  }
  
                  request = icl_pdu_new(response->ip_conn, M_NOWAIT);
                  if (request == NULL) {
                          icl_pdu_free(response);
                          iscsi_session_reconnect(is);
                          return;
                  }
  
                  bhsdo = (struct iscsi_bhs_data_out *)request->ip_bhs;
                  bhsdo->bhsdo_opcode = ISCSI_BHS_OPCODE_SCSI_DATA_OUT;
                  bhsdo->bhsdo_lun = bhsr2t->bhsr2t_lun;
                  bhsdo->bhsdo_initiator_task_tag =
                      bhsr2t->bhsr2t_initiator_task_tag;
                  bhsdo->bhsdo_target_transfer_tag =
                      bhsr2t->bhsr2t_target_transfer_tag;
                  bhsdo->bhsdo_datasn = htonl(datasn);
                  bhsdo->bhsdo_buffer_offset = htonl(off);
                  error = iscsi_pdu_append_data_csio(request, csio, off, len,
                      M_NOWAIT | ICL_NOCOPY);
                  if (error != 0) {
                          ISCSI_SESSION_WARN(is, "failed to allocate memory; "
                              "reconnecting");
                          icl_pdu_free(request);
                          icl_pdu_free(response);
                          iscsi_session_reconnect(is);
                          return;
                  }
  
                  datasn += howmany(len,
                      is->is_conn->ic_max_send_data_segment_length);
                  off += len;
                  total_len -= len;
  
                  if (total_len == 0) {
                          bhsdo->bhsdo_flags |= BHSDO_FLAGS_F;
                          //ISCSI_SESSION_DEBUG(is, "setting F, off %zd", off);
                  } else {
                          //ISCSI_SESSION_DEBUG(is, "not finished, off %zd", off);
                  }
  
                  iscsi_pdu_queue_locked(request);
  
                  if (total_len == 0)
                          break;
          }
  
          icl_pdu_free(response);
  }
  
  static void
  iscsi_pdu_handle_async_message(struct icl_pdu *response)
  {
          struct iscsi_bhs_asynchronous_message *bhsam;
          struct iscsi_session *is;
  
          is = PDU_SESSION(response);
          bhsam = (struct iscsi_bhs_asynchronous_message *)response->ip_bhs;
          switch (bhsam->bhsam_async_event) {
          case BHSAM_EVENT_TARGET_REQUESTS_LOGOUT:
                  ISCSI_SESSION_WARN(is, "target requests logout; removing session");
                  iscsi_session_logout(is);
                  iscsi_session_terminate(is);
                  break;
          case BHSAM_EVENT_TARGET_TERMINATES_CONNECTION:
                  ISCSI_SESSION_WARN(is, "target indicates it will drop the connection");
                  break;
          case BHSAM_EVENT_TARGET_TERMINATES_SESSION:
                  ISCSI_SESSION_WARN(is, "target indicates it will drop the session");
                  break;
          default:
                  /*
                   * XXX: Technically, we're obligated to also handle
                   *      parameter renegotiation.
                   */
                  ISCSI_SESSION_WARN(is, "ignoring AsyncEvent %d", bhsam->bhsam_async_event);
                  break;
          }
  
          icl_pdu_free(response);
  }
  
  static void
  iscsi_pdu_handle_reject(struct icl_pdu *response)
  {
          struct iscsi_bhs_reject *bhsr;
          struct iscsi_session *is;
  
          is = PDU_SESSION(response);
          bhsr = (struct iscsi_bhs_reject *)response->ip_bhs;
          ISCSI_SESSION_WARN(is, "received Reject PDU, reason 0x%x; protocol error?",
              bhsr->bhsr_reason);
  
          icl_pdu_free(response);
  }
  
  static int
  iscsi_ioctl_daemon_wait(struct iscsi_softc *sc,
      struct iscsi_daemon_request *request, bool freebsd13)
  {
          struct iscsi_session *is;
          int error;
  
          sx_slock(&sc->sc_lock);
          for (;;) {
                  TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                          ISCSI_SESSION_LOCK(is);
                          if (is->is_conf.isc_enable == 0 &&
                              is->is_conf.isc_discovery == 0) {
                                  ISCSI_SESSION_UNLOCK(is);
                                  continue;
                          }
                          if (is->is_waiting_for_iscsid)
                                  break;
                          ISCSI_SESSION_UNLOCK(is);
                  }
  
                  if (is == NULL) {
                          if (sc->sc_unloading) {
                                  sx_sunlock(&sc->sc_lock);
                                  return (ENXIO);
                          }
  
                          /*
                           * No session requires attention from iscsid(8); wait.
                           */
                          error = cv_wait_sig(&sc->sc_cv, &sc->sc_lock);
                          if (error != 0) {
                                  sx_sunlock(&sc->sc_lock);
                                  return (error);
                          }
                          continue;
                  }
  
                  is->is_waiting_for_iscsid = false;
                  is->is_login_phase = true;
                  is->is_reason[0] = '\0';
                  ISCSI_SESSION_UNLOCK(is);
  
                  request->idr_session_id = is->is_id;
                  memcpy(&request->idr_isid, &is->is_isid,
                      sizeof(request->idr_isid));
                  request->idr_tsih = 0;  /* New or reinstated session. */
                  memcpy(&request->idr_conf, &is->is_conf,
                      sizeof(request->idr_conf));
  
  #ifdef COMPAT_FREEBSD13
                  if (freebsd13) {
                          struct icl_drv_limits idl;
                          struct iscsi_daemon_request13 *request13;
  
                          error = icl_limits(is->is_conf.isc_offload,
                              is->is_conf.isc_iser, 0, &idl);
                          if (error != 0) {
                                  ISCSI_SESSION_WARN(is, "icl_limits for "
                                      "offload \"%s\" failed with error %d",
                                      is->is_conf.isc_offload, error);
                                  sx_sunlock(&sc->sc_lock);
                                  return (error);
                          }
                          request13 = (struct iscsi_daemon_request13 *)request;
                          request13->idr_limits.isl_max_recv_data_segment_length =
                              idl.idl_max_recv_data_segment_length;
                          request13->idr_limits.isl_max_send_data_segment_length =
                              idl.idl_max_send_data_segment_length;
                          request13->idr_limits.isl_max_burst_length =
                              idl.idl_max_burst_length;
                          request13->idr_limits.isl_first_burst_length =
                              idl.idl_first_burst_length;
                  }
  #endif
                  sx_sunlock(&sc->sc_lock);
                  return (0);
          }
  }
  
  static int
  iscsi_ioctl_daemon_limits(struct iscsi_softc *sc,
      struct iscsi_daemon_limits *limits)
  {
          struct icl_drv_limits idl;
          struct iscsi_session *is;
          int error;
  
          sx_slock(&sc->sc_lock);
  
          /*
           * Find the session to fetch limits for.
           */
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                  if (is->is_id == limits->idl_session_id)
                          break;
          }
          if (is == NULL) {
                  sx_sunlock(&sc->sc_lock);
                  return (ESRCH);
          }
  
          error = icl_limits(is->is_conf.isc_offload, is->is_conf.isc_iser,
              limits->idl_socket, &idl);
          sx_sunlock(&sc->sc_lock);
          if (error != 0) {
                  ISCSI_SESSION_WARN(is, "icl_limits for offload \"%s\" "
                      "failed with error %d", is->is_conf.isc_offload, error);
                  return (error);
          }
          limits->idl_limits.isl_max_recv_data_segment_length =
              idl.idl_max_recv_data_segment_length;
          limits->idl_limits.isl_max_send_data_segment_length =
              idl.idl_max_send_data_segment_length;
          limits->idl_limits.isl_max_burst_length =
              idl.idl_max_burst_length;
          limits->idl_limits.isl_first_burst_length =
              idl.idl_first_burst_length;
          
          return (0);
  }
  
  static int
  iscsi_ioctl_daemon_handoff(struct iscsi_softc *sc,
      struct iscsi_daemon_handoff *handoff)
  {
          struct iscsi_session *is;
          struct icl_conn *ic;
          int error;
  
          sx_slock(&sc->sc_lock);
  
          /*
           * Find the session to hand off socket to.
           */
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                  if (is->is_id == handoff->idh_session_id)
                          break;
          }
          if (is == NULL) {
                  sx_sunlock(&sc->sc_lock);
                  return (ESRCH);
          }
          ISCSI_SESSION_LOCK(is);
          ic = is->is_conn;
          if (is->is_conf.isc_discovery || is->is_terminating) {
                  ISCSI_SESSION_UNLOCK(is);
                  sx_sunlock(&sc->sc_lock);
                  return (EINVAL);
          }
          if (is->is_connected) {
                  /*
                   * This might have happened because another iscsid(8)
                   * instance handed off the connection in the meantime.
                   * Just return.
                   */
                  ISCSI_SESSION_WARN(is, "handoff on already connected "
                      "session");
                  ISCSI_SESSION_UNLOCK(is);
                  sx_sunlock(&sc->sc_lock);
                  return (EBUSY);
          }
  
          strlcpy(is->is_target_alias, handoff->idh_target_alias,
              sizeof(is->is_target_alias));
          is->is_tsih = handoff->idh_tsih;
          is->is_statsn = handoff->idh_statsn;
          is->is_protocol_level = handoff->idh_protocol_level;
          is->is_initial_r2t = handoff->idh_initial_r2t;
          is->is_immediate_data = handoff->idh_immediate_data;
  
          ic->ic_max_recv_data_segment_length =
              handoff->idh_max_recv_data_segment_length;
          ic->ic_max_send_data_segment_length =
              handoff->idh_max_send_data_segment_length;
          is->is_max_burst_length = handoff->idh_max_burst_length;
          is->is_first_burst_length = handoff->idh_first_burst_length;
  
          if (handoff->idh_header_digest == ISCSI_DIGEST_CRC32C)
                  ic->ic_header_crc32c = true;
          else
                  ic->ic_header_crc32c = false;
          if (handoff->idh_data_digest == ISCSI_DIGEST_CRC32C)
                  ic->ic_data_crc32c = true;
          else
                  ic->ic_data_crc32c = false;
          ic->ic_maxtags = maxtags;
  
          is->is_cmdsn = 0;
          is->is_expcmdsn = 0;
          is->is_maxcmdsn = 0;
          is->is_waiting_for_iscsid = false;
          is->is_login_phase = false;
          is->is_timeout = 0;
          is->is_ping_timeout = is->is_conf.isc_ping_timeout;
          if (is->is_ping_timeout < 0)
                  is->is_ping_timeout = ping_timeout;
          is->is_login_timeout = is->is_conf.isc_login_timeout;
          if (is->is_login_timeout < 0)
                  is->is_login_timeout = login_timeout;
          is->is_connected = true;
          is->is_reason[0] = '\0';
  
          ISCSI_SESSION_UNLOCK(is);
  
          /*
           * If we're going through the proxy, the idh_socket will be 0,
           * and the ICL module can simply ignore this call.  It can also
           * use it to determine it's no longer in the Login phase.
           */
          error = icl_conn_handoff(ic, handoff->idh_socket);
          if (error != 0) {
                  sx_sunlock(&sc->sc_lock);
                  iscsi_session_terminate(is);
                  return (error);
          }
  
          sx_sunlock(&sc->sc_lock);
  
          if (is->is_sim != NULL) {
                  /*
                   * When reconnecting, there already is SIM allocated for the session.
                   */
                  KASSERT(is->is_simq_frozen, ("reconnect without frozen simq"));
                  ISCSI_SESSION_LOCK(is);
                  ISCSI_SESSION_DEBUG(is, "releasing");
                  is->is_simq_frozen = false;
                  xpt_release_simq(is->is_sim, 1);
                  ISCSI_SESSION_UNLOCK(is);
  
          } else {
                  ISCSI_SESSION_LOCK(is);
                  is->is_devq = cam_simq_alloc(ic->ic_maxtags);
                  if (is->is_devq == NULL) {
                          ISCSI_SESSION_UNLOCK(is);
                          ISCSI_SESSION_WARN(is, "failed to allocate simq");
                          iscsi_session_terminate(is);
                          return (ENOMEM);
                  }
  
                  is->is_sim = cam_sim_alloc(iscsi_action, NULL, "iscsi",
                      is, is->is_id /* unit */, &is->is_lock,
                      1, ic->ic_maxtags, is->is_devq);
                  if (is->is_sim == NULL) {
                          ISCSI_SESSION_UNLOCK(is);
                          ISCSI_SESSION_WARN(is, "failed to allocate SIM");
                          cam_simq_free(is->is_devq);
                          iscsi_session_terminate(is);
                          return (ENOMEM);
                  }
  
                  if (xpt_bus_register(is->is_sim, NULL, 0) != 0) {
                          ISCSI_SESSION_UNLOCK(is);
                          ISCSI_SESSION_WARN(is, "failed to register bus");
                          iscsi_session_terminate(is);
                          return (ENOMEM);
                  }
  
                  error = xpt_create_path(&is->is_path, /*periph*/NULL,
                      cam_sim_path(is->is_sim), CAM_TARGET_WILDCARD,
                      CAM_LUN_WILDCARD);
                  if (error != CAM_REQ_CMP) {
                          ISCSI_SESSION_UNLOCK(is);
                          ISCSI_SESSION_WARN(is, "failed to create path");
                          iscsi_session_terminate(is);
                          return (ENOMEM);
                  }
                  ISCSI_SESSION_UNLOCK(is);
          }
  
          return (0);
  }
  
  static int
  iscsi_ioctl_daemon_fail(struct iscsi_softc *sc,
      struct iscsi_daemon_fail *fail)
  {
          struct iscsi_session *is;
  
          sx_slock(&sc->sc_lock);
  
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                  if (is->is_id == fail->idf_session_id)
                          break;
          }
          if (is == NULL) {
                  sx_sunlock(&sc->sc_lock);
                  return (ESRCH);
          }
          ISCSI_SESSION_LOCK(is);
          ISCSI_SESSION_DEBUG(is, "iscsid(8) failed: %s",
              fail->idf_reason);
          strlcpy(is->is_reason, fail->idf_reason, sizeof(is->is_reason));
          //is->is_waiting_for_iscsid = false;
          //is->is_login_phase = true;
          //iscsi_session_reconnect(is);
          ISCSI_SESSION_UNLOCK(is);
          sx_sunlock(&sc->sc_lock);
  
          return (0);
  }
  
  #ifdef ICL_KERNEL_PROXY
  static int
  iscsi_ioctl_daemon_connect(struct iscsi_softc *sc,
      struct iscsi_daemon_connect *idc)
  {
          struct iscsi_session *is;
          struct sockaddr *from_sa, *to_sa;
          int error;
  
          sx_slock(&sc->sc_lock);
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                  if (is->is_id == idc->idc_session_id)
                          break;
          }
          if (is == NULL) {
                  sx_sunlock(&sc->sc_lock);
                  return (ESRCH);
          }
          sx_sunlock(&sc->sc_lock);
  
          if (idc->idc_from_addrlen > 0) {
                  error = getsockaddr(&from_sa, (void *)idc->idc_from_addr, idc->idc_from_addrlen);
                  if (error != 0) {
                          ISCSI_SESSION_WARN(is,
                              "getsockaddr failed with error %d", error);
                          return (error);
                  }
          } else {
                  from_sa = NULL;
          }
          error = getsockaddr(&to_sa, (void *)idc->idc_to_addr, idc->idc_to_addrlen);
          if (error != 0) {
                  ISCSI_SESSION_WARN(is, "getsockaddr failed with error %d",
                      error);
                  free(from_sa, M_SONAME);
                  return (error);
          }
  
          ISCSI_SESSION_LOCK(is);
          is->is_statsn = 0;
          is->is_cmdsn = 0;
          is->is_expcmdsn = 0;
          is->is_maxcmdsn = 0;
          is->is_waiting_for_iscsid = false;
          is->is_login_phase = true;
          is->is_timeout = 0;
          ISCSI_SESSION_UNLOCK(is);
  
          error = icl_conn_connect(is->is_conn, idc->idc_domain,
              idc->idc_socktype, idc->idc_protocol, from_sa, to_sa);
          free(from_sa, M_SONAME);
          free(to_sa, M_SONAME);
  
          /*
           * Digests are always disabled during login phase.
           */
          is->is_conn->ic_header_crc32c = false;
          is->is_conn->ic_data_crc32c = false;
  
          return (error);
  }
  
  static int
  iscsi_ioctl_daemon_send(struct iscsi_softc *sc,
      struct iscsi_daemon_send *ids)
  {
          struct iscsi_session *is;
          struct icl_pdu *ip;
          size_t datalen;
          void *data;
          int error;
  
          sx_slock(&sc->sc_lock);
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                  if (is->is_id == ids->ids_session_id)
                          break;
          }
          if (is == NULL) {
                  sx_sunlock(&sc->sc_lock);
                  return (ESRCH);
          }
          sx_sunlock(&sc->sc_lock);
  
          if (is->is_login_phase == false)
                  return (EBUSY);
  
          if (is->is_terminating || is->is_reconnecting)
                  return (EIO);
  
          datalen = ids->ids_data_segment_len;
          if (datalen > is->is_conn->ic_max_send_data_segment_length)
                  return (EINVAL);
          if (datalen > 0) {
                  data = malloc(datalen, M_ISCSI, M_WAITOK);
                  error = copyin(ids->ids_data_segment, data, datalen);
                  if (error != 0) {
                          free(data, M_ISCSI);
                          return (error);
                  }
          }
  
          ip = icl_pdu_new(is->is_conn, M_WAITOK);
          memcpy(ip->ip_bhs, ids->ids_bhs, sizeof(*ip->ip_bhs));
          if (datalen > 0) {
                  error = icl_pdu_append_data(ip, data, datalen, M_WAITOK);
                  KASSERT(error == 0, ("icl_pdu_append_data(..., M_WAITOK) failed"));
                  free(data, M_ISCSI);
          }
          iscsi_pdu_queue(ip);
  
          return (0);
  }
  
  static int
  iscsi_ioctl_daemon_receive(struct iscsi_softc *sc,
      struct iscsi_daemon_receive *idr)
  {
          struct iscsi_session *is;
          struct icl_pdu *ip;
          void *data;
          int error;
  
          sx_slock(&sc->sc_lock);
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                  if (is->is_id == idr->idr_session_id)
                          break;
          }
          if (is == NULL) {
                  sx_sunlock(&sc->sc_lock);
                  return (ESRCH);
          }
          sx_sunlock(&sc->sc_lock);
  
          if (is->is_login_phase == false)
                  return (EBUSY);
  
          ISCSI_SESSION_LOCK(is);
          while (is->is_login_pdu == NULL &&
              is->is_terminating == false &&
              is->is_reconnecting == false) {
                  error = cv_wait_sig(&is->is_login_cv, &is->is_lock);
                  if (error != 0) {
                          ISCSI_SESSION_UNLOCK(is);
                          return (error);
                  }
          }
          if (is->is_terminating || is->is_reconnecting) {
                  ISCSI_SESSION_UNLOCK(is);
                  return (EIO);
          }
          ip = is->is_login_pdu;
          is->is_login_pdu = NULL;
          ISCSI_SESSION_UNLOCK(is);
  
          if (ip->ip_data_len > idr->idr_data_segment_len) {
                  icl_pdu_free(ip);
                  return (EMSGSIZE);
          }
  
          copyout(ip->ip_bhs, idr->idr_bhs, sizeof(*ip->ip_bhs));
          if (ip->ip_data_len > 0) {
                  data = malloc(ip->ip_data_len, M_ISCSI, M_WAITOK);
                  icl_pdu_get_data(ip, 0, data, ip->ip_data_len);
                  copyout(data, idr->idr_data_segment, ip->ip_data_len);
                  free(data, M_ISCSI);
          }
  
          icl_pdu_free(ip);
  
          return (0);
  }
  #endif /* ICL_KERNEL_PROXY */
  
  static void
  iscsi_sanitize_session_conf(struct iscsi_session_conf *isc)
  {
          /*
           * Just make sure all the fields are null-terminated.
           *
           * XXX: This is not particularly secure.  We should
           *      create our own conf and then copy in relevant
           *      fields.
           */
          isc->isc_initiator[ISCSI_NAME_LEN - 1] = '\0';
          isc->isc_initiator_addr[ISCSI_ADDR_LEN - 1] = '\0';
          isc->isc_initiator_alias[ISCSI_ALIAS_LEN - 1] = '\0';
          isc->isc_target[ISCSI_NAME_LEN - 1] = '\0';
          isc->isc_target_addr[ISCSI_ADDR_LEN - 1] = '\0';
          isc->isc_user[ISCSI_NAME_LEN - 1] = '\0';
          isc->isc_secret[ISCSI_SECRET_LEN - 1] = '\0';
          isc->isc_mutual_user[ISCSI_NAME_LEN - 1] = '\0';
          isc->isc_mutual_secret[ISCSI_SECRET_LEN - 1] = '\0';
  }
  
  static bool
  iscsi_valid_session_conf(const struct iscsi_session_conf *isc)
  {
  
          if (isc->isc_initiator[0] == '\0') {
                  ISCSI_DEBUG("empty isc_initiator");
                  return (false);
          }
  
          if (isc->isc_target_addr[0] == '\0') {
                  ISCSI_DEBUG("empty isc_target_addr");
                  return (false);
          }
  
          if (isc->isc_discovery != 0 && isc->isc_target[0] != 0) {
                  ISCSI_DEBUG("non-empty isc_target for discovery session");
                  return (false);
          }
  
          if (isc->isc_discovery == 0 && isc->isc_target[0] == 0) {
                  ISCSI_DEBUG("empty isc_target for non-discovery session");
                  return (false);
          }
  
          return (true);
  }
  
  static int
  iscsi_ioctl_session_add(struct iscsi_softc *sc, struct iscsi_session_add *isa)
  {
          struct iscsi_session *is;
          const struct iscsi_session *is2;
          int error;
          sbintime_t sbt, pr;
  
          iscsi_sanitize_session_conf(&isa->isa_conf);
          if (iscsi_valid_session_conf(&isa->isa_conf) == false)
                  return (EINVAL);
  
          is = malloc(sizeof(*is), M_ISCSI, M_ZERO | M_WAITOK);
          memcpy(&is->is_conf, &isa->isa_conf, sizeof(is->is_conf));
  
          sx_xlock(&sc->sc_lock);
  
          /*
           * Prevent duplicates.
           */
          TAILQ_FOREACH(is2, &sc->sc_sessions, is_next) {
                  if (!!is->is_conf.isc_discovery !=
                      !!is2->is_conf.isc_discovery)
                          continue;
  
                  if (strcmp(is->is_conf.isc_target_addr,
                      is2->is_conf.isc_target_addr) != 0)
                          continue;
  
                  if (is->is_conf.isc_discovery == 0 &&
                      strcmp(is->is_conf.isc_target,
                      is2->is_conf.isc_target) != 0)
                          continue;
  
                  sx_xunlock(&sc->sc_lock);
                  free(is, M_ISCSI);
                  return (EBUSY);
          }
  
          is->is_conn = icl_new_conn(is->is_conf.isc_offload,
              is->is_conf.isc_iser, "iscsi", &is->is_lock);
          if (is->is_conn == NULL) {
                  sx_xunlock(&sc->sc_lock);
                  free(is, M_ISCSI);
                  return (EINVAL);
          }
          is->is_conn->ic_receive = iscsi_receive_callback;
          is->is_conn->ic_error = iscsi_error_callback;
          is->is_conn->ic_prv0 = is;
          TAILQ_INIT(&is->is_outstanding);
          STAILQ_INIT(&is->is_postponed);
          mtx_init(&is->is_lock, "iscsi_lock", NULL, MTX_DEF);
          cv_init(&is->is_maintenance_cv, "iscsi_mt");
  #ifdef ICL_KERNEL_PROXY
          cv_init(&is->is_login_cv, "iscsi_login");
  #endif
  
          /*
           * Set some default values, from RFC 3720, section 12.
           *
           * These values are updated by the handoff IOCTL, but are
           * needed prior to the handoff to support sending the ISER
           * login PDU.
           */
          is->is_conn->ic_max_recv_data_segment_length = 8192;
          is->is_conn->ic_max_send_data_segment_length = 8192;
          is->is_max_burst_length = 262144;
          is->is_first_burst_length = 65536;
  
          is->is_softc = sc;
          sc->sc_last_session_id++;
          is->is_id = sc->sc_last_session_id;
          is->is_isid[0] = 0x80; /* RFC 3720, 10.12.5: 10b, "Random" ISID. */
          arc4rand(&is->is_isid[1], 5, 0);
          is->is_tsih = 0;
          callout_init(&is->is_callout, 1);
  
          error = kthread_add(iscsi_maintenance_thread, is, NULL, NULL, 0, 0, "iscsimt");
          if (error != 0) {
                  ISCSI_SESSION_WARN(is, "kthread_add(9) failed with error %d", error);
                  sx_xunlock(&sc->sc_lock);
                  return (error);
          }
          is->is_ping_timeout = is->is_conf.isc_ping_timeout;
          if (is->is_ping_timeout < 0)
                  is->is_ping_timeout = ping_timeout;
          is->is_login_timeout = is->is_conf.isc_login_timeout;
          if (is->is_login_timeout < 0)
                  is->is_login_timeout = login_timeout;
  
          sbt = mstosbt(995);
          pr = mstosbt(10);
          callout_reset_sbt(&is->is_callout, sbt, pr, iscsi_callout, is, 0);
          TAILQ_INSERT_TAIL(&sc->sc_sessions, is, is_next);
  
          ISCSI_SESSION_LOCK(is);
          /*
           * Don't notify iscsid(8) if the session is disabled and it's not
           * a discovery session,
           */
          if (is->is_conf.isc_enable == 0 && is->is_conf.isc_discovery == 0) {
                  ISCSI_SESSION_UNLOCK(is);
                  sx_xunlock(&sc->sc_lock);
                  return (0);
          }
  
          is->is_waiting_for_iscsid = true;
          strlcpy(is->is_reason, "Waiting for iscsid(8)", sizeof(is->is_reason));
          ISCSI_SESSION_UNLOCK(is);
          cv_signal(&sc->sc_cv);
          sx_xunlock(&sc->sc_lock);
          return (0);
  }
  
  static bool
  iscsi_session_conf_matches(unsigned int id1, const struct iscsi_session_conf *c1,
      unsigned int id2, const struct iscsi_session_conf *c2)
  {
  
          if (id2 != 0 && id2 != id1)
                  return (false);
          if (c2->isc_target[0] != '\0' &&
              strcmp(c1->isc_target, c2->isc_target) != 0)
                  return (false);
          if (c2->isc_target_addr[0] != '\0' &&
              strcmp(c1->isc_target_addr, c2->isc_target_addr) != 0)
                  return (false);
          return (true);
  }
  
  static int
  iscsi_ioctl_session_remove(struct iscsi_softc *sc,
      struct iscsi_session_remove *isr)
  {
          struct iscsi_session *is, *tmp;
          bool found = false;
  
          iscsi_sanitize_session_conf(&isr->isr_conf);
  
          sx_xlock(&sc->sc_lock);
          TAILQ_FOREACH_SAFE(is, &sc->sc_sessions, is_next, tmp) {
                  ISCSI_SESSION_LOCK(is);
                  if (iscsi_session_conf_matches(is->is_id, &is->is_conf,
                      isr->isr_session_id, &isr->isr_conf)) {
                          found = true;
                          iscsi_session_logout(is);
                          iscsi_session_terminate(is);
                  }
                  ISCSI_SESSION_UNLOCK(is);
          }
          sx_xunlock(&sc->sc_lock);
  
          if (!found)
                  return (ESRCH);
  
          return (0);
  }
  
  static int
  iscsi_ioctl_session_list(struct iscsi_softc *sc, struct iscsi_session_list *isl)
  {
          int error;
          unsigned int i = 0;
          struct iscsi_session *is;
          struct iscsi_session_state iss;
  
          sx_slock(&sc->sc_lock);
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                  if (i >= isl->isl_nentries) {
                          sx_sunlock(&sc->sc_lock);
                          return (EMSGSIZE);
                  }
                  memset(&iss, 0, sizeof(iss));
                  memcpy(&iss.iss_conf, &is->is_conf, sizeof(iss.iss_conf));
                  iss.iss_id = is->is_id;
                  strlcpy(iss.iss_target_alias, is->is_target_alias, sizeof(iss.iss_target_alias));
                  strlcpy(iss.iss_reason, is->is_reason, sizeof(iss.iss_reason));
                  strlcpy(iss.iss_offload, is->is_conn->ic_offload, sizeof(iss.iss_offload));
  
                  if (is->is_conn->ic_header_crc32c)
                          iss.iss_header_digest = ISCSI_DIGEST_CRC32C;
                  else
                          iss.iss_header_digest = ISCSI_DIGEST_NONE;
  
                  if (is->is_conn->ic_data_crc32c)
                          iss.iss_data_digest = ISCSI_DIGEST_CRC32C;
                  else
                          iss.iss_data_digest = ISCSI_DIGEST_NONE;
  
                  iss.iss_max_send_data_segment_length =
                      is->is_conn->ic_max_send_data_segment_length;
                  iss.iss_max_recv_data_segment_length =
                      is->is_conn->ic_max_recv_data_segment_length;
                  iss.iss_max_burst_length = is->is_max_burst_length;
                  iss.iss_first_burst_length = is->is_first_burst_length;
                  iss.iss_immediate_data = is->is_immediate_data;
                  iss.iss_connected = is->is_connected;
  
                  error = copyout(&iss, isl->isl_pstates + i, sizeof(iss));
                  if (error != 0) {
                          sx_sunlock(&sc->sc_lock);
                          return (error);
                  }
                  i++;
          }
          sx_sunlock(&sc->sc_lock);
  
          isl->isl_nentries = i;
  
          return (0);
  }
  
  static int
  iscsi_ioctl_session_modify(struct iscsi_softc *sc,
      struct iscsi_session_modify *ism)
  {
          struct iscsi_session *is;
          const struct iscsi_session *is2;
  
          iscsi_sanitize_session_conf(&ism->ism_conf);
          if (iscsi_valid_session_conf(&ism->ism_conf) == false)
                  return (EINVAL);
  
          sx_xlock(&sc->sc_lock);
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                  ISCSI_SESSION_LOCK(is);
                  if (is->is_id == ism->ism_session_id) {
                          /* Note that the session remains locked. */
                          break;
                  }
                  ISCSI_SESSION_UNLOCK(is);
          }
          if (is == NULL) {
                  sx_xunlock(&sc->sc_lock);
                  return (ESRCH);
          }
  
          /*
           * Prevent duplicates.
           */
          TAILQ_FOREACH(is2, &sc->sc_sessions, is_next) {
                  if (is == is2)
                          continue;
  
                  if (!!ism->ism_conf.isc_discovery !=
                      !!is2->is_conf.isc_discovery)
                          continue;
  
                  if (strcmp(ism->ism_conf.isc_target_addr,
                      is2->is_conf.isc_target_addr) != 0)
                          continue;
  
                  if (ism->ism_conf.isc_discovery == 0 &&
                      strcmp(ism->ism_conf.isc_target,
                      is2->is_conf.isc_target) != 0)
                          continue;
  
                  ISCSI_SESSION_UNLOCK(is);
                  sx_xunlock(&sc->sc_lock);
                  return (EBUSY);
          }
  
          sx_xunlock(&sc->sc_lock);
  
          memcpy(&is->is_conf, &ism->ism_conf, sizeof(is->is_conf));
          ISCSI_SESSION_UNLOCK(is);
  
          iscsi_session_reconnect(is);
  
          return (0);
  }
  
  static int
  iscsi_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int mode,
      struct thread *td)
  {
          struct iscsi_softc *sc;
  
          sc = dev->si_drv1;
  
          switch (cmd) {
          case ISCSIDWAIT:
                  return (iscsi_ioctl_daemon_wait(sc,
                      (struct iscsi_daemon_request *)arg, false));
  #ifdef COMPAT_FREEBSD13
          case ISCSIDWAIT13:
                  return (iscsi_ioctl_daemon_wait(sc,
                      (struct iscsi_daemon_request *)arg, true));
  #endif
          case ISCSIDLIMITS:
                  return (iscsi_ioctl_daemon_limits(sc,
                      (struct iscsi_daemon_limits *)arg));
          case ISCSIDHANDOFF:
                  return (iscsi_ioctl_daemon_handoff(sc,
                      (struct iscsi_daemon_handoff *)arg));
          case ISCSIDFAIL:
                  return (iscsi_ioctl_daemon_fail(sc,
                      (struct iscsi_daemon_fail *)arg));
  #ifdef ICL_KERNEL_PROXY
          case ISCSIDCONNECT:
                  return (iscsi_ioctl_daemon_connect(sc,
                      (struct iscsi_daemon_connect *)arg));
          case ISCSIDSEND:
                  return (iscsi_ioctl_daemon_send(sc,
                      (struct iscsi_daemon_send *)arg));
          case ISCSIDRECEIVE:
                  return (iscsi_ioctl_daemon_receive(sc,
                      (struct iscsi_daemon_receive *)arg));
  #endif /* ICL_KERNEL_PROXY */
          case ISCSISADD:
                  return (iscsi_ioctl_session_add(sc,
                      (struct iscsi_session_add *)arg));
          case ISCSISREMOVE:
                  return (iscsi_ioctl_session_remove(sc,
                      (struct iscsi_session_remove *)arg));
          case ISCSISLIST:
                  return (iscsi_ioctl_session_list(sc,
                      (struct iscsi_session_list *)arg));
          case ISCSISMODIFY:
                  return (iscsi_ioctl_session_modify(sc,
                      (struct iscsi_session_modify *)arg));
          default:
                  return (EINVAL);
          }
  }
  
  static struct iscsi_outstanding *
  iscsi_outstanding_find(struct iscsi_session *is, uint32_t initiator_task_tag)
  {
          struct iscsi_outstanding *io;
  
          ISCSI_SESSION_LOCK_ASSERT(is);
  
          TAILQ_FOREACH(io, &is->is_outstanding, io_next) {
                  if (io->io_initiator_task_tag == initiator_task_tag)
                          return (io);
          }
          return (NULL);
  }
  
  static struct iscsi_outstanding *
  iscsi_outstanding_find_ccb(struct iscsi_session *is, union ccb *ccb)
  {
          struct iscsi_outstanding *io;
  
          ISCSI_SESSION_LOCK_ASSERT(is);
  
          TAILQ_FOREACH(io, &is->is_outstanding, io_next) {
                  if (io->io_ccb == ccb)
                          return (io);
          }
          return (NULL);
  }
  
  static struct iscsi_outstanding *
  iscsi_outstanding_add(struct iscsi_session *is, struct icl_pdu *request,
      union ccb *ccb, uint32_t *initiator_task_tagp)
  {
          struct iscsi_outstanding *io;
          int error;
  
          ISCSI_SESSION_LOCK_ASSERT(is);
  
          io = uma_zalloc(iscsi_outstanding_zone, M_NOWAIT | M_ZERO);
          if (io == NULL) {
                  ISCSI_SESSION_WARN(is, "failed to allocate %zd bytes",
                      sizeof(*io));
                  return (NULL);
          }
  
          error = icl_conn_task_setup(is->is_conn, request, &ccb->csio,
              initiator_task_tagp, &io->io_icl_prv);
          if (error != 0) {
                  ISCSI_SESSION_WARN(is,
                      "icl_conn_task_setup() failed with error %d", error);
                  uma_zfree(iscsi_outstanding_zone, io);
                  return (NULL);
          }
  
          KASSERT(iscsi_outstanding_find(is, *initiator_task_tagp) == NULL,
              ("initiator_task_tag 0x%x already added", *initiator_task_tagp));
  
          io->io_initiator_task_tag = *initiator_task_tagp;
          io->io_ccb = ccb;
          TAILQ_INSERT_TAIL(&is->is_outstanding, io, io_next);
          return (io);
  }
  
  static void
  iscsi_outstanding_remove(struct iscsi_session *is, struct iscsi_outstanding *io)
  {
  
          ISCSI_SESSION_LOCK_ASSERT(is);
  
          icl_conn_task_done(is->is_conn, io->io_icl_prv);
          TAILQ_REMOVE(&is->is_outstanding, io, io_next);
          uma_zfree(iscsi_outstanding_zone, io);
  }
  
  static void
  iscsi_action_abort(struct iscsi_session *is, union ccb *ccb)
  {
          struct icl_pdu *request;
          struct iscsi_bhs_task_management_request *bhstmr;
          struct ccb_abort *cab = &ccb->cab;
          struct iscsi_outstanding *io, *aio;
          uint32_t initiator_task_tag;
  
          ISCSI_SESSION_LOCK_ASSERT(is);
  
  #if 0
          KASSERT(is->is_login_phase == false, ("%s called during Login Phase", __func__));
  #else
          if (is->is_login_phase) {
                  ccb->ccb_h.status = CAM_REQ_ABORTED;
                  xpt_done(ccb);
                  return;
          }
  #endif
  
          aio = iscsi_outstanding_find_ccb(is, cab->abort_ccb);
          if (aio == NULL) {
                  ccb->ccb_h.status = CAM_REQ_CMP;
                  xpt_done(ccb);
                  return;
          }
  
          request = icl_pdu_new(is->is_conn, M_NOWAIT);
          if (request == NULL) {
                  ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
                  xpt_done(ccb);
                  return;
          }
  
          initiator_task_tag = is->is_initiator_task_tag++;
          if (initiator_task_tag == 0xffffffff)
                  initiator_task_tag = is->is_initiator_task_tag++;
  
          io = iscsi_outstanding_add(is, request, NULL, &initiator_task_tag);
          if (io == NULL) {
                  icl_pdu_free(request);
                  ccb->ccb_h.status = CAM_RESRC_UNAVAIL;
                  xpt_done(ccb);
                  return;
          }
          io->io_referenced_task_tag = aio->io_initiator_task_tag;
  
          bhstmr = (struct iscsi_bhs_task_management_request *)request->ip_bhs;
          bhstmr->bhstmr_opcode = ISCSI_BHS_OPCODE_TASK_REQUEST;
          bhstmr->bhstmr_function = 0x80 | BHSTMR_FUNCTION_ABORT_TASK;
          bhstmr->bhstmr_lun = htobe64(CAM_EXTLUN_BYTE_SWIZZLE(ccb->ccb_h.target_lun));
          bhstmr->bhstmr_initiator_task_tag = initiator_task_tag;
          bhstmr->bhstmr_referenced_task_tag = aio->io_initiator_task_tag;
  
          iscsi_pdu_queue_locked(request);
  }
  
  static void
  iscsi_action_scsiio(struct iscsi_session *is, union ccb *ccb)
  {
          struct icl_pdu *request;
          struct iscsi_bhs_scsi_command *bhssc;
          struct ccb_scsiio *csio;
          struct iscsi_outstanding *io;
          size_t len;
          uint32_t initiator_task_tag;
          int error;
  
          ISCSI_SESSION_LOCK_ASSERT(is);
  
  #if 0
          KASSERT(is->is_login_phase == false, ("%s called during Login Phase", __func__));
  #else
          if (is->is_login_phase) {
                  ISCSI_SESSION_DEBUG(is, "called during login phase");
                  if ((ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                          xpt_freeze_devq(ccb->ccb_h.path, 1);
                          ISCSI_SESSION_DEBUG(is, "freezing devq");
                  }
                  ccb->ccb_h.status = CAM_REQ_ABORTED | CAM_DEV_QFRZN;
                  xpt_done(ccb);
                  return;
          }
  #endif
  
          request = icl_pdu_new(is->is_conn, M_NOWAIT);
          if (request == NULL) {
                  if ((ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                          xpt_freeze_devq(ccb->ccb_h.path, 1);
                          ISCSI_SESSION_DEBUG(is, "freezing devq");
                  }
                  ccb->ccb_h.status = CAM_RESRC_UNAVAIL | CAM_DEV_QFRZN;
                  xpt_done(ccb);
                  return;
          }
  
          initiator_task_tag = is->is_initiator_task_tag++;
          if (initiator_task_tag == 0xffffffff)
                  initiator_task_tag = is->is_initiator_task_tag++;
  
          io = iscsi_outstanding_add(is, request, ccb, &initiator_task_tag);
          if (io == NULL) {
                  icl_pdu_free(request);
                  if ((ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                          xpt_freeze_devq(ccb->ccb_h.path, 1);
                          ISCSI_SESSION_DEBUG(is, "freezing devq");
                  }
                  ccb->ccb_h.status = CAM_RESRC_UNAVAIL | CAM_DEV_QFRZN;
                  xpt_done(ccb);
                  return;
          }
  
          csio = &ccb->csio;
          bhssc = (struct iscsi_bhs_scsi_command *)request->ip_bhs;
          bhssc->bhssc_opcode = ISCSI_BHS_OPCODE_SCSI_COMMAND;
          bhssc->bhssc_flags |= BHSSC_FLAGS_F;
          switch (csio->ccb_h.flags & CAM_DIR_MASK) {
          case CAM_DIR_IN:
                  bhssc->bhssc_flags |= BHSSC_FLAGS_R;
                  break;
          case CAM_DIR_OUT:
                  bhssc->bhssc_flags |= BHSSC_FLAGS_W;
                  break;
          }
  
          if ((ccb->ccb_h.flags & CAM_TAG_ACTION_VALID) != 0) {
                  switch (csio->tag_action) {
                  case MSG_HEAD_OF_Q_TAG:
                          bhssc->bhssc_flags |= BHSSC_FLAGS_ATTR_HOQ;
                          break;
                  case MSG_ORDERED_Q_TAG:
                          bhssc->bhssc_flags |= BHSSC_FLAGS_ATTR_ORDERED;
                          break;
                  case MSG_ACA_TASK:
                          bhssc->bhssc_flags |= BHSSC_FLAGS_ATTR_ACA;
                          break;
                  case MSG_SIMPLE_Q_TAG:
                  default:
                          bhssc->bhssc_flags |= BHSSC_FLAGS_ATTR_SIMPLE;
                          break;
                  }
          } else
                  bhssc->bhssc_flags |= BHSSC_FLAGS_ATTR_UNTAGGED;
  
          if (is->is_protocol_level >= 2) {
                  bhssc->bhssc_pri = (csio->priority << BHSSC_PRI_SHIFT) &
                      BHSSC_PRI_MASK;
          }
  
          bhssc->bhssc_lun = htobe64(CAM_EXTLUN_BYTE_SWIZZLE(ccb->ccb_h.target_lun));
          bhssc->bhssc_initiator_task_tag = initiator_task_tag;
          bhssc->bhssc_expected_data_transfer_length = htonl(csio->dxfer_len);
          KASSERT(csio->cdb_len <= sizeof(bhssc->bhssc_cdb),
              ("unsupported CDB size %zd", (size_t)csio->cdb_len));
  
          if (csio->ccb_h.flags & CAM_CDB_POINTER)
                  memcpy(&bhssc->bhssc_cdb, csio->cdb_io.cdb_ptr, csio->cdb_len);
          else
                  memcpy(&bhssc->bhssc_cdb, csio->cdb_io.cdb_bytes, csio->cdb_len);
  
          if (is->is_immediate_data &&
              (csio->ccb_h.flags & CAM_DIR_MASK) == CAM_DIR_OUT) {
                  len = csio->dxfer_len;
                  //ISCSI_SESSION_DEBUG(is, "adding %zd of immediate data", len);
                  if (len > is->is_first_burst_length) {
                          ISCSI_SESSION_DEBUG(is, "len %zd -> %d", len, is->is_first_burst_length);
                          len = is->is_first_burst_length;
                  }
                  if (len > is->is_conn->ic_max_send_data_segment_length) {
                          ISCSI_SESSION_DEBUG(is, "len %zd -> %d", len,
                              is->is_conn->ic_max_send_data_segment_length);
                          len = is->is_conn->ic_max_send_data_segment_length;
                  }
  
                  error = iscsi_pdu_append_data_csio(request, csio, 0, len,
                      M_NOWAIT | ICL_NOCOPY);
                  if (error != 0) {
                          iscsi_outstanding_remove(is, io);
                          icl_pdu_free(request);
                          if ((ccb->ccb_h.status & CAM_DEV_QFRZN) == 0) {
                                  xpt_freeze_devq(ccb->ccb_h.path, 1);
                                  ISCSI_SESSION_DEBUG(is, "freezing devq");
                          }
                          ccb->ccb_h.status = CAM_RESRC_UNAVAIL | CAM_DEV_QFRZN;
                          xpt_done(ccb);
                          return;
                  }
          }
          iscsi_pdu_queue_locked(request);
  }
  
  static void
  iscsi_action(struct cam_sim *sim, union ccb *ccb)
  {
          struct iscsi_session *is;
  
          is = cam_sim_softc(sim);
  
          ISCSI_SESSION_LOCK_ASSERT(is);
  
          if (is->is_terminating ||
              (is->is_connected == false && fail_on_disconnection)) {
                  ccb->ccb_h.status = CAM_DEV_NOT_THERE;
                  xpt_done(ccb);
                  return;
          }
  
          /*
           * Make sure CAM doesn't sneak in a CCB just after freezing the queue.
           */
          if (is->is_simq_frozen == true) {
                  ccb->ccb_h.status &= ~(CAM_SIM_QUEUED | CAM_STATUS_MASK);
                  ccb->ccb_h.status |= CAM_REQUEUE_REQ;
                  /* Don't freeze the devq - the SIM queue is already frozen. */
                  xpt_done(ccb);
                  return;
          }
  
          switch (ccb->ccb_h.func_code) {
          case XPT_PATH_INQ:
          {
                  struct ccb_pathinq *cpi = &ccb->cpi;
  
                  cpi->version_num = 1;
                  cpi->hba_inquiry = PI_TAG_ABLE;
                  cpi->target_sprt = 0;
                  cpi->hba_misc = PIM_EXTLUNS;
                  /*
                   * XXX: It shouldn't ever be NULL; this could be turned
                   *      into a KASSERT eventually.
                   */
                  if (is->is_conn == NULL)
                          ISCSI_WARN("NULL conn");
                  else if (is->is_conn->ic_unmapped)
                          cpi->hba_misc |= PIM_UNMAPPED;
                  cpi->hba_eng_cnt = 0;
                  cpi->max_target = 0;
                  /*
                   * Note that the variable below is only relevant for targets
                   * that don't claim compliance with anything above SPC2, which
                   * means they don't support REPORT_LUNS.
                   */
                  cpi->max_lun = 255;
                  cpi->initiator_id = ~0;
                  strlcpy(cpi->sim_vid, "FreeBSD", SIM_IDLEN);
                  strlcpy(cpi->hba_vid, "iSCSI", HBA_IDLEN);
                  strlcpy(cpi->dev_name, cam_sim_name(sim), DEV_IDLEN);
                  cpi->unit_number = cam_sim_unit(sim);
                  cpi->bus_id = cam_sim_bus(sim);
                  cpi->base_transfer_speed = 150000; /* XXX */
                  cpi->transport = XPORT_ISCSI;
                  cpi->transport_version = 0;
                  cpi->protocol = PROTO_SCSI;
                  cpi->protocol_version = SCSI_REV_SPC3;
                  cpi->maxio = maxphys;
                  cpi->ccb_h.status = CAM_REQ_CMP;
                  break;
          }
          case XPT_GET_TRAN_SETTINGS:
          {
                  struct ccb_trans_settings       *cts;
                  struct ccb_trans_settings_scsi  *scsi;
  
                  cts = &ccb->cts;
                  scsi = &cts->proto_specific.scsi;
  
                  cts->protocol = PROTO_SCSI;
                  cts->protocol_version = SCSI_REV_SPC3;
                  cts->transport = XPORT_ISCSI;
                  cts->transport_version = 0;
                  scsi->valid = CTS_SCSI_VALID_TQ;
                  scsi->flags = CTS_SCSI_FLAGS_TAG_ENB;
                  cts->ccb_h.status = CAM_REQ_CMP;
                  break;
          }
          case XPT_CALC_GEOMETRY:
                  cam_calc_geometry(&ccb->ccg, /*extended*/1);
                  ccb->ccb_h.status = CAM_REQ_CMP;
                  break;
  #if 0
          /*
           * XXX: What's the point?
           */
          case XPT_RESET_BUS:
          case XPT_TERM_IO:
                  ISCSI_SESSION_DEBUG(is, "faking success for reset, abort, or term_io");
                  ccb->ccb_h.status = CAM_REQ_CMP;
                  break;
  #endif
          case XPT_ABORT:
                  iscsi_action_abort(is, ccb);
                  return;
          case XPT_SCSI_IO:
                  iscsi_action_scsiio(is, ccb);
                  return;
          default:
  #if 0
                  ISCSI_SESSION_DEBUG(is, "got unsupported code 0x%x", ccb->ccb_h.func_code);
  #endif
                  ccb->ccb_h.status = CAM_FUNC_NOTAVAIL;
                  break;
          }
          xpt_done(ccb);
  }
  
  static void
  iscsi_terminate_sessions(struct iscsi_softc *sc)
  {
          struct iscsi_session *is;
  
          sx_slock(&sc->sc_lock);
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next)
                  iscsi_session_terminate(is);
          while(!TAILQ_EMPTY(&sc->sc_sessions)) {
                  ISCSI_DEBUG("waiting for sessions to terminate");
                  cv_wait(&sc->sc_cv, &sc->sc_lock);
          }
          ISCSI_DEBUG("all sessions terminated");
          sx_sunlock(&sc->sc_lock);
  }
  
  static void
  iscsi_shutdown_pre(struct iscsi_softc *sc)
  {
          struct iscsi_session *is;
  
          if (!fail_on_shutdown)
                  return;
  
          /*
           * If we have any sessions waiting for reconnection, request
           * maintenance thread to fail them immediately instead of waiting
           * for reconnect timeout.
           *
           * This prevents LUNs with mounted filesystems that are supported
           * by disconnected iSCSI sessions from hanging, however it will
           * fail all queued BIOs.
           */
          ISCSI_DEBUG("forcing failing all disconnected sessions due to shutdown");
  
          fail_on_disconnection = 1;
  
          sx_slock(&sc->sc_lock);
          TAILQ_FOREACH(is, &sc->sc_sessions, is_next) {
                  ISCSI_SESSION_LOCK(is);
                  if (!is->is_connected) {
                          ISCSI_SESSION_DEBUG(is, "force failing disconnected session early");
                          iscsi_session_reconnect(is);
                  }
                  ISCSI_SESSION_UNLOCK(is);
          }
          sx_sunlock(&sc->sc_lock);
  }
  
  static void
  iscsi_shutdown_post(struct iscsi_softc *sc)
  {
  
          if (!KERNEL_PANICKED()) {
                  ISCSI_DEBUG("removing all sessions due to shutdown");
                  iscsi_terminate_sessions(sc);
          }
  }
  
  static int
  iscsi_load(void)
  {
          int error;
  
          sc = malloc(sizeof(*sc), M_ISCSI, M_ZERO | M_WAITOK);
          sx_init(&sc->sc_lock, "iscsi");
          TAILQ_INIT(&sc->sc_sessions);
          cv_init(&sc->sc_cv, "iscsi_cv");
  
          iscsi_outstanding_zone = uma_zcreate("iscsi_outstanding",
              sizeof(struct iscsi_outstanding), NULL, NULL, NULL, NULL,
              UMA_ALIGN_PTR, 0);
  
          error = make_dev_p(MAKEDEV_CHECKNAME, &sc->sc_cdev, &iscsi_cdevsw,
              NULL, UID_ROOT, GID_WHEEL, 0600, "iscsi");
          if (error != 0) {
                  ISCSI_WARN("failed to create device node, error %d", error);
                  return (error);
          }
          sc->sc_cdev->si_drv1 = sc;
  
          sc->sc_shutdown_pre_eh = EVENTHANDLER_REGISTER(shutdown_pre_sync,
              iscsi_shutdown_pre, sc, SHUTDOWN_PRI_FIRST);
          /*
           * shutdown_post_sync needs to run after filesystem shutdown and before
           * CAM shutdown - otherwise when rebooting with an iSCSI session that is
           * disconnected but has outstanding requests, dashutdown() will hang on
           * cam_periph_runccb().
           */
          sc->sc_shutdown_post_eh = EVENTHANDLER_REGISTER(shutdown_post_sync,
              iscsi_shutdown_post, sc, SHUTDOWN_PRI_DEFAULT - 1);
  
          return (0);
  }
  
  static int
  iscsi_unload(void)
  {
  
          /* Awaken any threads asleep in iscsi_ioctl(). */
          sx_xlock(&sc->sc_lock);
          sc->sc_unloading = true;
          cv_signal(&sc->sc_cv);
          sx_xunlock(&sc->sc_lock);
  
          if (sc->sc_cdev != NULL) {
                  ISCSI_DEBUG("removing device node");
                  destroy_dev(sc->sc_cdev);
                  ISCSI_DEBUG("device node removed");
          }
  
          if (sc->sc_shutdown_pre_eh != NULL)
                  EVENTHANDLER_DEREGISTER(shutdown_pre_sync, sc->sc_shutdown_pre_eh);
          if (sc->sc_shutdown_post_eh != NULL)
                  EVENTHANDLER_DEREGISTER(shutdown_post_sync, sc->sc_shutdown_post_eh);
  
          iscsi_terminate_sessions(sc);
  
          uma_zdestroy(iscsi_outstanding_zone);
          sx_destroy(&sc->sc_lock);
          cv_destroy(&sc->sc_cv);
          free(sc, M_ISCSI);
          return (0);
  }
  
  static int
  iscsi_quiesce(void)
  {
          sx_slock(&sc->sc_lock);
          if (!TAILQ_EMPTY(&sc->sc_sessions)) {
                  sx_sunlock(&sc->sc_lock);
                  return (EBUSY);
          }
          sx_sunlock(&sc->sc_lock);
          return (0);
  }
  
  static int
  iscsi_modevent(module_t mod, int what, void *arg)
  {
          int error;
  
          switch (what) {
          case MOD_LOAD:
                  error = iscsi_load();
                  break;
          case MOD_UNLOAD:
                  error = iscsi_unload();
                  break;
          case MOD_QUIESCE:
                  error = iscsi_quiesce();
                  break;
          default:
                  error = EINVAL;
                  break;
          }
          return (error);
  }
  
  moduledata_t iscsi_data = {
          "iscsi",
          iscsi_modevent,
          0
  };
  
  DECLARE_MODULE(iscsi, iscsi_data, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
  MODULE_DEPEND(iscsi, cam, 1, 1, 1);
  MODULE_DEPEND(iscsi, icl, 1, 1, 1);

Cache object: dd56141be9e9bc1da9a207bfee5c66dd