io/dld/dld_str.c

	dld_str.c revision 1a5e258f5471356ca102c7176637cdce45bac147
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * Data-Link Driver
 */

#include    <inet/common.h>
#include    <sys/strsubr.h>
#include    <sys/stropts.h>
#include    <sys/strsun.h>
#include    <sys/vlan.h>
#include    <sys/dld_impl.h>
#include    <sys/cpuvar.h>
#include    <sys/callb.h>
#include    <sys/list.h>
#include    <sys/mac_client.h>
#include    <sys/mac_client_priv.h>
#include    <sys/mac_flow.h>

static int  str_constructor(void *, void *, int);
static void str_destructor(void *, void *);
static mblk_t   *str_unitdata_ind(dld_str_t *, mblk_t *, boolean_t);
static void str_notify_promisc_on_phys(dld_str_t *);
static void str_notify_promisc_off_phys(dld_str_t *);
static void str_notify_phys_addr(dld_str_t *, uint_t, const uint8_t *);
static void str_notify_link_up(dld_str_t *);
static void str_notify_link_down(dld_str_t *);
static void str_notify_capab_reneg(dld_str_t *);
static void str_notify_speed(dld_str_t *, uint32_t);

static void ioc_native(dld_str_t *,  mblk_t *);
static void ioc_margin(dld_str_t *, mblk_t *);
static void ioc_raw(dld_str_t *, mblk_t *);
static void ioc_fast(dld_str_t *,  mblk_t *);
static void ioc_lowlink(dld_str_t *,  mblk_t *);
static void ioc(dld_str_t *, mblk_t *);
static void dld_ioc(dld_str_t *, mblk_t *);
static void dld_wput_nondata(dld_str_t *, mblk_t *);

static void str_mdata_raw_put(dld_str_t *, mblk_t *);
static mblk_t   *i_dld_ether_header_update_tag(mblk_t *, uint_t, uint16_t,
    link_tagmode_t);
static mblk_t   *i_dld_ether_header_strip_tag(mblk_t *, boolean_t);

static uint32_t     str_count;
static kmem_cache_t *str_cachep;
static mod_hash_t   *str_hashp;

#define STR_HASHSZ      64
#define STR_HASH_KEY(key)   ((mod_hash_key_t)(uintptr_t)(key))

#define dld_taskq   system_taskq

static kmutex_t     dld_taskq_lock;
static kcondvar_t   dld_taskq_cv;
static list_t       dld_taskq_list;     /* List of dld_str_t */
boolean_t       dld_taskq_quit;
boolean_t       dld_taskq_done;

static void     dld_taskq_dispatch(void);

/*
 * Some notes on entry points, flow-control, queueing.
 *
 * This driver exports the traditional STREAMS put entry point as well as
 * the non-STREAMS fast-path transmit routine which is provided to IP via
 * the DL_CAPAB_POLL negotiation.  The put procedure handles all control
 * and data operations, while the fast-path routine deals only with M_DATA
 * fast-path packets.  Regardless of the entry point, all outbound packets
 * will end up in DLD_TX(), where they will be delivered to the MAC layer.
 *
 * The transmit logic operates in the following way: All packets coming
 * into DLD will be sent to the MAC layer through DLD_TX(). Flow-control
 * happens when the MAC layer indicates the packets couldn't be
 * transmitted due to 1) lack of resources (e.g. running out of
 * descriptors),  or 2) reaching the allowed bandwidth limit for this
 * particular flow. The indication comes in the form of a Tx cookie that
 * identifies the blocked ring. In such case, DLD will place a
 * dummy message on its write-side STREAMS queue so that the queue is
 * marked as "full". Any subsequent packets arriving at the driver will
 * still be sent to the MAC layer where it either gets queued in the Tx
 * SRS or discarded it if queue limit is exceeded. The write-side STREAMS
 * queue gets enabled when MAC layer notifies DLD through MAC_NOTE_TX.
 * When the write service procedure runs, it will remove the dummy
 * message from the write-side STREAMS queue; in effect this will trigger
 * backenabling. The sizes of q_hiwat and q_lowat are set to 1 and 0,
 * respectively, due to the above reasons.
 *
 * All non-data operations, both DLPI and ioctls are single threaded on a per
 * dld_str_t endpoint. This is done using a taskq so that the control operation
 * has kernel context and can cv_wait for resources. In addition all set type
 * operations that involve mac level state modification are serialized on a
 * per mac end point using the perimeter mechanism provided by the mac layer.
 * This serializes all mac clients trying to modify a single mac end point over
 * the entire sequence of mac calls made by that client as an atomic unit. The
 * mac framework locking is described in mac.c. A critical element is that
 * DLD/DLS does not hold any locks across the mac perimeter.
 *
 * dld_finddevinfo() returns the dev_info_t * corresponding to a particular
 * dev_t. It searches str_hashp (a table of dld_str_t's) for streams that
 * match dev_t. If a stream is found and it is attached, its dev_info_t *
 * is returned. If the mac handle is non-null, it can be safely accessed
 * below. The mac handle won't be freed until the mac_unregister which
 * won't happen until the driver detaches. The DDI framework ensures that
 * the detach won't happen while a getinfo is in progress.
 */
typedef struct i_dld_str_state_s {
    major_t     ds_major;
    minor_t     ds_minor;
    int     ds_instance;
    dev_info_t  *ds_dip;
} i_dld_str_state_t;

/* ARGSUSED */
static uint_t
i_dld_str_walker(mod_hash_key_t key, mod_hash_val_t *val, void *arg)
{
    i_dld_str_state_t   *statep = arg;
    dld_str_t       *dsp = (dld_str_t *)val;
    mac_handle_t        mh;

    if (statep->ds_major != dsp->ds_major)
        return (MH_WALK_CONTINUE);

    ASSERT(statep->ds_minor != 0);
    mh = dsp->ds_mh;

    if (statep->ds_minor == dsp->ds_minor) {
        /*
         * Clone: a clone minor is unique. we can terminate the
         * walk if we find a matching stream -- even if we fail
         * to obtain the devinfo.
         */
        if (mh != NULL) {
            statep->ds_dip = mac_devinfo_get(mh);
            statep->ds_instance = DLS_MINOR2INST(mac_minor(mh));
        }
        return (MH_WALK_TERMINATE);
    }
    return (MH_WALK_CONTINUE);
}

static dev_info_t *
dld_finddevinfo(dev_t dev)
{
    dev_info_t      *dip;
    i_dld_str_state_t   state;

    if (getminor(dev) == 0)
        return (NULL);

    /*
     * See if it's a minor node of a link
     */
    if ((dip = dls_link_devinfo(dev)) != NULL)
        return (dip);

    state.ds_minor = getminor(dev);
    state.ds_major = getmajor(dev);
    state.ds_dip = NULL;
    state.ds_instance = -1;

    mod_hash_walk(str_hashp, i_dld_str_walker, &state);
    return (state.ds_dip);
}

int
dld_devt_to_instance(dev_t dev)
{
    minor_t         minor;
    i_dld_str_state_t   state;

    /*
     * GLDv3 numbers DLPI style 1 node as the instance number + 1.
     * Minor number 0 is reserved for the DLPI style 2 unattached
     * node.
     */

    if ((minor = getminor(dev)) == 0)
        return (-1);

    /*
     * Check for unopened style 1 node.
     * Note that this doesn't *necessarily* work for legacy
     * devices, but this code is only called within the
     * getinfo(9e) implementation for true GLDv3 devices, so it
     * doesn't matter.
     */
    if (minor > 0 && minor <= DLS_MAX_MINOR) {
        return (DLS_MINOR2INST(minor));
    }

    state.ds_minor = getminor(dev);
    state.ds_major = getmajor(dev);
    state.ds_dip = NULL;
    state.ds_instance = -1;

    mod_hash_walk(str_hashp, i_dld_str_walker, &state);
    return (state.ds_instance);
}

/*
 * devo_getinfo: getinfo(9e)
 *
 * NB: This may be called for a provider before the provider's
 * instances are attached.  Hence, if a particular provider needs a
 * special mapping (the mac instance != ddi_get_instance()), then it
 * may need to provide its own implmentation using the
 * mac_devt_to_instance() function, and translating the returned mac
 * instance to a devinfo instance.  For dev_t's where the minor number
 * is too large (i.e. > MAC_MAX_MINOR), the provider can call this
 * function indirectly via the mac_getinfo() function.
 */
/*ARGSUSED*/
int
dld_getinfo(dev_info_t *dip, ddi_info_cmd_t cmd, void *arg, void **resp)
{
    dev_info_t  *devinfo;
    minor_t     minor = getminor((dev_t)arg);
    int     rc = DDI_FAILURE;

    switch (cmd) {
    case DDI_INFO_DEVT2DEVINFO:
        if ((devinfo = dld_finddevinfo((dev_t)arg)) != NULL) {
            *(dev_info_t **)resp = devinfo;
            rc = DDI_SUCCESS;
        }
        break;
    case DDI_INFO_DEVT2INSTANCE:
        if (minor > 0 && minor <= DLS_MAX_MINOR) {
            *resp = (void *)(uintptr_t)DLS_MINOR2INST(minor);
            rc = DDI_SUCCESS;
        } else if (minor > DLS_MAX_MINOR &&
            (devinfo = dld_finddevinfo((dev_t)arg)) != NULL) {
            *resp = (void *)(uintptr_t)ddi_get_instance(devinfo);
            rc = DDI_SUCCESS;
        }
        break;
    }
    return (rc);
}

void *
dld_str_private(queue_t *q)
{
    return (((dld_str_t *)(q->q_ptr))->ds_private);
}

int
dld_str_open(queue_t *rq, dev_t *devp, void *private)
{
    dld_str_t   *dsp;
    major_t     major;
    minor_t     minor;
    int     err;

    major = getmajor(*devp);
    minor = getminor(*devp);

    /*
     * Create a new dld_str_t for the stream. This will grab a new minor
     * number that will be handed back in the cloned dev_t.  Creation may
     * fail if we can't allocate the dummy mblk used for flow-control.
     */
    dsp = dld_str_create(rq, DLD_DLPI, major,
        ((minor == 0) ? DL_STYLE2 : DL_STYLE1));
    if (dsp == NULL)
        return (ENOSR);

    ASSERT(dsp->ds_dlstate == DL_UNATTACHED);
    dsp->ds_private = private;
    if (minor != 0) {
        /*
         * Style 1 open
         */
        if ((err = dld_str_attach(dsp, (t_uscalar_t)minor - 1)) != 0)
            goto failed;

        ASSERT(dsp->ds_dlstate == DL_UNBOUND);
    } else {
        (void) qassociate(rq, -1);
    }

    /*
     * Enable the queue srv(9e) routine.
     */
    qprocson(rq);

    /*
     * Construct a cloned dev_t to hand back.
     */
    *devp = makedevice(getmajor(*devp), dsp->ds_minor);
    return (0);

failed:
    dld_str_destroy(dsp);
    return (err);
}

int
dld_str_close(queue_t *rq)
{
    dld_str_t   *dsp = rq->q_ptr;

    /*
     * All modules on top have been popped off. So there can't be any
     * threads from the top.
     */
    ASSERT(dsp->ds_datathr_cnt == 0);

    /*
     * Wait until pending DLPI requests are processed.
     */
    mutex_enter(&dsp->ds_lock);
    while (dsp->ds_dlpi_pending)
        cv_wait(&dsp->ds_dlpi_pending_cv, &dsp->ds_lock);
    mutex_exit(&dsp->ds_lock);


    /*
     * This stream was open to a provider node. Check to see
     * if it has been cleanly shut down.
     */
    if (dsp->ds_dlstate != DL_UNATTACHED) {
        /*
         * The stream is either open to a style 1 provider or
         * this is not clean shutdown. Detach from the PPA.
         * (This is still ok even in the style 1 case).
         */
        dld_str_detach(dsp);
    }

    dld_str_destroy(dsp);
    return (0);
}

/*
 * qi_qopen: open(9e)
 */
/*ARGSUSED*/
int
dld_open(queue_t *rq, dev_t *devp, int flag, int sflag, cred_t *credp)
{
    if (sflag == MODOPEN)
        return (ENOTSUP);

    /*
     * This is a cloning driver and therefore each queue should only
     * ever get opened once.
     */
    if (rq->q_ptr != NULL)
        return (EBUSY);

    return (dld_str_open(rq, devp, NULL));
}

/*
 * qi_qclose: close(9e)
 */
int
dld_close(queue_t *rq)
{
    /*
     * Disable the queue srv(9e) routine.
     */
    qprocsoff(rq);

    return (dld_str_close(rq));
}

/*
 * qi_qputp: put(9e)
 */
void
dld_wput(queue_t *wq, mblk_t *mp)
{
    dld_str_t *dsp = (dld_str_t *)wq->q_ptr;
    dld_str_mode_t  mode;

    switch (DB_TYPE(mp)) {
    case M_DATA:
        mutex_enter(&dsp->ds_lock);
        mode = dsp->ds_mode;
        if ((dsp->ds_dlstate != DL_IDLE) ||
            (mode != DLD_FASTPATH && mode != DLD_RAW)) {
            mutex_exit(&dsp->ds_lock);
            freemsg(mp);
            break;
        }

        DLD_DATATHR_INC(dsp);
        mutex_exit(&dsp->ds_lock);
        if (mode == DLD_FASTPATH) {
            if (dsp->ds_mip->mi_media == DL_ETHER &&
                (MBLKL(mp) < sizeof (struct ether_header))) {
                freemsg(mp);
            } else {
                (void) str_mdata_fastpath_put(dsp, mp, 0, 0);
            }
        } else {
            str_mdata_raw_put(dsp, mp);
        }
        DLD_DATATHR_DCR(dsp);
        break;
    case M_PROTO:
    case M_PCPROTO: {
        t_uscalar_t prim;

        if (MBLKL(mp) < sizeof (t_uscalar_t))
            break;

        prim = ((union DL_primitives *)mp->b_rptr)->dl_primitive;

        if (prim == DL_UNITDATA_REQ) {
            proto_unitdata_req(dsp, mp);
        } else {
            dld_wput_nondata(dsp, mp);
        }
        break;
    }

    case M_IOCTL:
        dld_wput_nondata(dsp, mp);
        break;

    case M_FLUSH:
        if (*mp->b_rptr & FLUSHW) {
            DLD_CLRQFULL(dsp);
            *mp->b_rptr &= ~FLUSHW;
        }

        if (*mp->b_rptr & FLUSHR) {
            qreply(wq, mp);
        } else {
            freemsg(mp);
        }
        break;

    default:
        freemsg(mp);
        break;
    }
}

/*
 * qi_srvp: srv(9e)
 */
void
dld_wsrv(queue_t *wq)
{
    dld_str_t   *dsp = wq->q_ptr;

    DLD_CLRQFULL(dsp);
}

void
dld_init_ops(struct dev_ops *ops, const char *name)
{
    struct streamtab *stream;
    struct qinit *rq, *wq;
    struct module_info *modinfo;

    modinfo = kmem_zalloc(sizeof (struct module_info), KM_SLEEP);
    modinfo->mi_idname = kmem_zalloc(FMNAMESZ, KM_SLEEP);
    (void) snprintf(modinfo->mi_idname, FMNAMESZ, "%s", name);
    modinfo->mi_minpsz = 0;
    modinfo->mi_maxpsz = 64*1024;
    modinfo->mi_hiwat  = 1;
    modinfo->mi_lowat = 0;

    rq = kmem_zalloc(sizeof (struct qinit), KM_SLEEP);
    rq->qi_qopen = dld_open;
    rq->qi_qclose = dld_close;
    rq->qi_minfo = modinfo;

    wq = kmem_zalloc(sizeof (struct qinit), KM_SLEEP);
    wq->qi_putp = (pfi_t)dld_wput;
    wq->qi_srvp = (pfi_t)dld_wsrv;
    wq->qi_minfo = modinfo;

    stream = kmem_zalloc(sizeof (struct streamtab), KM_SLEEP);
    stream->st_rdinit = rq;
    stream->st_wrinit = wq;
    ops->devo_cb_ops->cb_str = stream;

    if (ops->devo_getinfo == NULL)
        ops->devo_getinfo = &dld_getinfo;
}

void
dld_fini_ops(struct dev_ops *ops)
{
    struct streamtab *stream;
    struct qinit *rq, *wq;
    struct module_info *modinfo;

    stream = ops->devo_cb_ops->cb_str;
    rq = stream->st_rdinit;
    wq = stream->st_wrinit;
    modinfo = rq->qi_minfo;
    ASSERT(wq->qi_minfo == modinfo);

    kmem_free(stream, sizeof (struct streamtab));
    kmem_free(wq, sizeof (struct qinit));
    kmem_free(rq, sizeof (struct qinit));
    kmem_free(modinfo->mi_idname, FMNAMESZ);
    kmem_free(modinfo, sizeof (struct module_info));
}

/*
 * Initialize this module's data structures.
 */
void
dld_str_init(void)
{
    /*
     * Create dld_str_t object cache.
     */
    str_cachep = kmem_cache_create("dld_str_cache", sizeof (dld_str_t),
        0, str_constructor, str_destructor, NULL, NULL, NULL, 0);
    ASSERT(str_cachep != NULL);

    /*
     * Create a hash table for maintaining dld_str_t's.
     * The ds_minor field (the clone minor number) of a dld_str_t
     * is used as a key for this hash table because this number is
     * globally unique (allocated from "dls_minor_arena").
     */
    str_hashp = mod_hash_create_idhash("dld_str_hash", STR_HASHSZ,
        mod_hash_null_valdtor);

    mutex_init(&dld_taskq_lock, NULL, MUTEX_DRIVER, NULL);
    cv_init(&dld_taskq_cv, NULL, CV_DRIVER, NULL);

    dld_taskq_quit = B_FALSE;
    dld_taskq_done = B_FALSE;
    list_create(&dld_taskq_list, sizeof (dld_str_t),
        offsetof(dld_str_t, ds_tqlist));
    (void) thread_create(NULL, 0, dld_taskq_dispatch, NULL, 0,
        &p0, TS_RUN, minclsyspri);
}

/*
 * Tear down this module's data structures.
 */
int
dld_str_fini(void)
{
    /*
     * Make sure that there are no objects in use.
     */
    if (str_count != 0)
        return (EBUSY);

    /*
     * Ask the dld_taskq thread to quit and wait for it to be done
     */
    mutex_enter(&dld_taskq_lock);
    dld_taskq_quit = B_TRUE;
    cv_signal(&dld_taskq_cv);
    while (!dld_taskq_done)
        cv_wait(&dld_taskq_cv, &dld_taskq_lock);
    mutex_exit(&dld_taskq_lock);
    list_destroy(&dld_taskq_list);
    /*
     * Destroy object cache.
     */
    kmem_cache_destroy(str_cachep);
    mod_hash_destroy_idhash(str_hashp);
    return (0);
}

/*
 * Create a new dld_str_t object.
 */
dld_str_t *
dld_str_create(queue_t *rq, uint_t type, major_t major, t_uscalar_t style)
{
    dld_str_t   *dsp;
    int     err;

    /*
     * Allocate an object from the cache.
     */
    atomic_inc_32(&str_count);
    dsp = kmem_cache_alloc(str_cachep, KM_SLEEP);

    /*
     * Allocate the dummy mblk for flow-control.
     */
    dsp->ds_tx_flow_mp = allocb(1, BPRI_HI);
    if (dsp->ds_tx_flow_mp == NULL) {
        kmem_cache_free(str_cachep, dsp);
        atomic_dec_32(&str_count);
        return (NULL);
    }
    dsp->ds_type = type;
    dsp->ds_major = major;
    dsp->ds_style = style;

    /*
     * Initialize the queue pointers.
     */
    ASSERT(RD(rq) == rq);
    dsp->ds_rq = rq;
    dsp->ds_wq = WR(rq);
    rq->q_ptr = WR(rq)->q_ptr = (void *)dsp;

    /*
     * We want explicit control over our write-side STREAMS queue
     * where the dummy mblk gets added/removed for flow-control.
     */
    noenable(WR(rq));

    err = mod_hash_insert(str_hashp, STR_HASH_KEY(dsp->ds_minor),
        (mod_hash_val_t)dsp);
    ASSERT(err == 0);
    return (dsp);
}

/*
 * Destroy a dld_str_t object.
 */
void
dld_str_destroy(dld_str_t *dsp)
{
    queue_t     *rq;
    queue_t     *wq;
    mod_hash_val_t  val;

    /*
     * Clear the queue pointers.
     */
    rq = dsp->ds_rq;
    wq = dsp->ds_wq;
    ASSERT(wq == WR(rq));
    rq->q_ptr = wq->q_ptr = NULL;
    dsp->ds_rq = dsp->ds_wq = NULL;

    ASSERT(dsp->ds_dlstate == DL_UNATTACHED);
    ASSERT(dsp->ds_sap == 0);
    ASSERT(dsp->ds_mh == NULL);
    ASSERT(dsp->ds_mch == NULL);
    ASSERT(dsp->ds_promisc == 0);
    ASSERT(dsp->ds_mph == NULL);
    ASSERT(dsp->ds_mip == NULL);
    ASSERT(dsp->ds_mnh == NULL);

    ASSERT(dsp->ds_polling == B_FALSE);
    ASSERT(dsp->ds_direct == B_FALSE);
    ASSERT(dsp->ds_lso == B_FALSE);
    ASSERT(dsp->ds_lso_max == 0);
    ASSERT(dsp->ds_passivestate != DLD_ACTIVE);

    /*
     * Reinitialize all the flags.
     */
    dsp->ds_notifications = 0;
    dsp->ds_passivestate = DLD_UNINITIALIZED;
    dsp->ds_mode = DLD_UNITDATA;
    dsp->ds_native = B_FALSE;
    dsp->ds_nonip = B_FALSE;

    ASSERT(dsp->ds_datathr_cnt == 0);
    ASSERT(dsp->ds_pending_head == NULL);
    ASSERT(dsp->ds_pending_tail == NULL);
    ASSERT(!dsp->ds_dlpi_pending);

    ASSERT(dsp->ds_dlp == NULL);
    ASSERT(dsp->ds_dmap == NULL);
    ASSERT(dsp->ds_rx == NULL);
    ASSERT(dsp->ds_rx_arg == NULL);
    ASSERT(dsp->ds_next == NULL);
    ASSERT(dsp->ds_head == NULL);

    /*
     * Free the dummy mblk if exists.
     */
    if (dsp->ds_tx_flow_mp != NULL) {
        freeb(dsp->ds_tx_flow_mp);
        dsp->ds_tx_flow_mp = NULL;
    }

    (void) mod_hash_remove(str_hashp, STR_HASH_KEY(dsp->ds_minor), &val);
    ASSERT(dsp == (dld_str_t *)val);

    /*
     * Free the object back to the cache.
     */
    kmem_cache_free(str_cachep, dsp);
    atomic_dec_32(&str_count);
}

/*
 * kmem_cache contructor function: see kmem_cache_create(9f).
 */
/*ARGSUSED*/
static int
str_constructor(void *buf, void *cdrarg, int kmflags)
{
    dld_str_t   *dsp = buf;

    bzero(buf, sizeof (dld_str_t));

    /*
     * Allocate a new minor number.
     */
    if ((dsp->ds_minor = mac_minor_hold(kmflags == KM_SLEEP)) == 0)
        return (-1);

    /*
     * Initialize the DLPI state machine.
     */
    dsp->ds_dlstate = DL_UNATTACHED;

    mutex_init(&dsp->ds_lock, NULL, MUTEX_DRIVER, NULL);
    cv_init(&dsp->ds_datathr_cv, NULL, CV_DRIVER, NULL);
    cv_init(&dsp->ds_dlpi_pending_cv, NULL, CV_DRIVER, NULL);

    return (0);
}

/*
 * kmem_cache destructor function.
 */
/*ARGSUSED*/
static void
str_destructor(void *buf, void *cdrarg)
{
    dld_str_t   *dsp = buf;

    /*
     * Release the minor number.
     */
    mac_minor_rele(dsp->ds_minor);

    ASSERT(dsp->ds_tx_flow_mp == NULL);

    mutex_destroy(&dsp->ds_lock);
    cv_destroy(&dsp->ds_datathr_cv);
    cv_destroy(&dsp->ds_dlpi_pending_cv);
}

/*
 * Update the priority bits and VID (may need to insert tag if mp points
 * to an untagged packet.
 * If vid is VLAN_ID_NONE, use the VID encoded in the packet.
 */
static mblk_t *
i_dld_ether_header_update_tag(mblk_t *mp, uint_t pri, uint16_t vid,
    link_tagmode_t tagmode)
{
    mblk_t *hmp;
    struct ether_vlan_header *evhp;
    struct ether_header *ehp;
    uint16_t old_tci = 0;
    size_t len;

    ASSERT(pri != 0 || vid != VLAN_ID_NONE);

    evhp = (struct ether_vlan_header *)mp->b_rptr;
    if (ntohs(evhp->ether_tpid) == ETHERTYPE_VLAN) {
        /*
         * Tagged packet, update the priority bits.
         */
        len = sizeof (struct ether_vlan_header);

        if ((DB_REF(mp) > 1) || (MBLKL(mp) < len)) {
            /*
             * In case some drivers only check the db_ref
             * count of the first mblk, we pullup the
             * message into a single mblk.
             */
            hmp = msgpullup(mp, -1);
            if ((hmp == NULL) || (MBLKL(hmp) < len)) {
                freemsg(hmp);
                return (NULL);
            } else {
                freemsg(mp);
                mp = hmp;
            }
        }

        evhp = (struct ether_vlan_header *)mp->b_rptr;
        old_tci = ntohs(evhp->ether_tci);
    } else {
        /*
         * Untagged packet.  Two factors will cause us to insert a
         * VLAN header:
         * - This is a VLAN link (vid is specified)
         * - The link supports user priority tagging and the priority
         *   is non-zero.
         */
        if (vid == VLAN_ID_NONE && tagmode == LINK_TAGMODE_VLANONLY)
            return (mp);

        hmp = allocb(sizeof (struct ether_vlan_header), BPRI_MED);
        if (hmp == NULL)
            return (NULL);

        evhp = (struct ether_vlan_header *)hmp->b_rptr;
        ehp = (struct ether_header *)mp->b_rptr;

        /*
         * Copy the MAC addresses and typelen
         */
        bcopy(ehp, evhp, (ETHERADDRL * 2));
        evhp->ether_type = ehp->ether_type;
        evhp->ether_tpid = htons(ETHERTYPE_VLAN);

        hmp->b_wptr += sizeof (struct ether_vlan_header);
        mp->b_rptr += sizeof (struct ether_header);

        /*
         * Free the original message if it's now empty. Link the
         * rest of the messages to the header message.
         */
        if (MBLKL(mp) == 0) {
            hmp->b_cont = mp->b_cont;
            freeb(mp);
        } else {
            hmp->b_cont = mp;
        }
        mp = hmp;
    }

    if (pri == 0)
        pri = VLAN_PRI(old_tci);
    if (vid == VLAN_ID_NONE)
        vid = VLAN_ID(old_tci);
    evhp->ether_tci = htons(VLAN_TCI(pri, VLAN_CFI(old_tci), vid));
    return (mp);
}

/*
 * M_DATA put (IP fast-path mode)
 */
mac_tx_cookie_t
str_mdata_fastpath_put(dld_str_t *dsp, mblk_t *mp, uintptr_t f_hint,
    uint16_t flag)
{
    boolean_t is_ethernet = (dsp->ds_mip->mi_media == DL_ETHER);
    mblk_t *newmp;
    uint_t pri;
    mac_tx_cookie_t cookie;

    if (is_ethernet) {
        /*
         * Update the priority bits to the assigned priority.
         */
        pri = (VLAN_MBLKPRI(mp) == 0) ? dsp->ds_pri : VLAN_MBLKPRI(mp);

        if (pri != 0) {
            newmp = i_dld_ether_header_update_tag(mp, pri,
                VLAN_ID_NONE, dsp->ds_dlp->dl_tagmode);
            if (newmp == NULL)
                goto discard;
            mp = newmp;
        }
    }

    if ((cookie = DLD_TX(dsp, mp, f_hint, flag)) != NULL) {
        DLD_SETQFULL(dsp);
    }
    return (cookie);

discard:
    /* TODO: bump kstat? */
    freemsg(mp);
    return (NULL);
}

/*
 * M_DATA put (DLIOCRAW mode)
 */
static void
str_mdata_raw_put(dld_str_t *dsp, mblk_t *mp)
{
    boolean_t is_ethernet = (dsp->ds_mip->mi_media == DL_ETHER);
    mblk_t *bp, *newmp;
    size_t size;
    mac_header_info_t mhi;
    uint_t pri, vid, dvid;
    uint_t max_sdu;

    /*
     * Certain MAC type plugins provide an illusion for raw DLPI
     * consumers.  They pretend that the MAC layer is something that
     * it's not for the benefit of observability tools.  For example,
     * mac_wifi pretends that it's Ethernet for such consumers.
     * Here, unless native mode is enabled, we call into the MAC layer so
     * that this illusion can be maintained.  The plugin will optionally
     * transform the MAC header here into something that can be passed
     * down.  The header goes from raw mode to "cooked" mode.
     */
    if (!dsp->ds_native) {
        if ((newmp = mac_header_cook(dsp->ds_mh, mp)) == NULL)
            goto discard;
        mp = newmp;
    }

    size = MBLKL(mp);

    /*
     * Check the packet is not too big and that any remaining
     * fragment list is composed entirely of M_DATA messages. (We
     * know the first fragment was M_DATA otherwise we could not
     * have got here).
     */
    for (bp = mp->b_cont; bp != NULL; bp = bp->b_cont) {
        if (DB_TYPE(bp) != M_DATA)
            goto discard;
        size += MBLKL(bp);
    }

    if (mac_vlan_header_info(dsp->ds_mh, mp, &mhi) != 0)
        goto discard;

    mac_sdu_get(dsp->ds_mh, NULL, &max_sdu);
    /*
     * If LSO is enabled, check the size against lso_max. Otherwise,
     * compare the packet size with max_sdu.
     */
    max_sdu = dsp->ds_lso ? dsp->ds_lso_max : max_sdu;
    if (size > max_sdu + mhi.mhi_hdrsize)
        goto discard;

    if (is_ethernet) {
        dvid = mac_client_vid(dsp->ds_mch);

        /*
         * Discard the packet if this is a VLAN stream but the VID in
         * the packet is not correct.
         */
        vid = VLAN_ID(mhi.mhi_tci);
        if ((dvid != VLAN_ID_NONE) && (vid != VLAN_ID_NONE))
            goto discard;

        /*
         * Discard the packet if this packet is a tagged packet
         * but both pri and VID are 0.
         */
        pri = VLAN_PRI(mhi.mhi_tci);
        if (mhi.mhi_istagged && !mhi.mhi_ispvid && pri == 0 &&
            vid == VLAN_ID_NONE)
            goto discard;

        /*
         * Update the priority bits to the per-stream priority if
         * priority is not set in the packet. Update the VID for
         * packets on a VLAN stream.
         */
        pri = (pri == 0) ? dsp->ds_pri : 0;
        if ((pri != 0) || (dvid != VLAN_ID_NONE)) {
            if ((newmp = i_dld_ether_header_update_tag(mp, pri,
                dvid, dsp->ds_dlp->dl_tagmode)) == NULL) {
                goto discard;
            }
            mp = newmp;
        }
    }

    if (DLD_TX(dsp, mp, 0, 0) != NULL) {
        /* Turn on flow-control for dld */
        DLD_SETQFULL(dsp);
    }
    return;

discard:
    /* TODO: bump kstat? */
    freemsg(mp);
}

/*
 * Process DL_ATTACH_REQ (style 2) or open(2) (style 1).
 */
int
dld_str_attach(dld_str_t *dsp, t_uscalar_t ppa)
{
    dev_t           dev;
    int         err;
    const char      *drvname;
    mac_perim_handle_t  mph = NULL;
    boolean_t       qassociated = B_FALSE;
    dls_link_t      *dlp = NULL;
    dls_dl_handle_t     ddp = NULL;

    if ((drvname = ddi_major_to_name(dsp->ds_major)) == NULL)
        return (EINVAL);

    if (dsp->ds_style == DL_STYLE2 && ppa > DLS_MAX_PPA)
        return (ENOTSUP);

    /*
     * /dev node access. This will still be supported for backward
     * compatibility reason.
     */
    if ((dsp->ds_style == DL_STYLE2) && (strcmp(drvname, "aggr") != 0) &&
        (strcmp(drvname, "vnic") != 0)) {
        if (qassociate(dsp->ds_wq, DLS_PPA2INST(ppa)) != 0)
            return (EINVAL);
        qassociated = B_TRUE;
    }

    dev = makedevice(dsp->ds_major, (minor_t)ppa + 1);
    if ((err = dls_devnet_hold_by_dev(dev, &ddp)) != 0)
        goto failed;

    if ((err = mac_perim_enter_by_macname(dls_devnet_mac(ddp), &mph)) != 0)
        goto failed;

    /*
     * Open a channel.
     */
    if ((err = dls_link_hold(dls_devnet_mac(ddp), &dlp)) != 0)
        goto failed;

    if ((err = dls_open(dlp, ddp, dsp)) != 0)
        goto failed;

    /*
     * Set the default packet priority.
     */
    dsp->ds_pri = 0;

    /*
     * Add a notify function so that the we get updates from the MAC.
     */
    dsp->ds_mnh = mac_notify_add(dsp->ds_mh, str_notify, dsp);
    dsp->ds_dlstate = DL_UNBOUND;
    mac_perim_exit(mph);
    return (0);

failed:
    if (dlp != NULL)
        dls_link_rele(dlp);
    if (mph != NULL)
        mac_perim_exit(mph);
    if (ddp != NULL)
        dls_devnet_rele(ddp);
    if (qassociated)
        (void) qassociate(dsp->ds_wq, -1);

    return (err);
}

/*
 * Process DL_DETACH_REQ (style 2) or close(2) (style 1). Can also be called
 * from close(2) for style 2.
 */
void
dld_str_detach(dld_str_t *dsp)
{
    mac_perim_handle_t  mph;
    int         err;

    ASSERT(dsp->ds_datathr_cnt == 0);

    mac_perim_enter_by_mh(dsp->ds_mh, &mph);
    /*
     * Remove the notify function.
     *
     * Note that we cannot wait for the notification callback to be removed
     * since it could cause the deadlock with str_notify() since they both
     * need the mac perimeter. Continue if we cannot remove the
     * notification callback right now and wait after we leave the
     * perimeter.
     */
    err = mac_notify_remove(dsp->ds_mnh, B_FALSE);
    dsp->ds_mnh = NULL;

    /*
     * Disable the capabilities
     */
    dld_capabilities_disable(dsp);

    /*
     * Clear LSO flags.
     */
    dsp->ds_lso = B_FALSE;
    dsp->ds_lso_max = 0;

    dls_close(dsp);
    mac_perim_exit(mph);

    /*
     * Now we leave the mac perimeter. If mac_notify_remove() failed
     * because the notification callback was in progress, wait for
     * it to finish before we proceed.
     */
    if (err != 0)
        mac_notify_remove_wait(dsp->ds_mh);

    /*
     * An unreferenced tagged (non-persistent) vlan gets destroyed
     * automatically in the call to dls_devnet_rele.
     */
    dls_devnet_rele(dsp->ds_ddh);

    dsp->ds_sap = 0;
    dsp->ds_mh = NULL;
    dsp->ds_mch = NULL;
    dsp->ds_mip = NULL;

    if (dsp->ds_style == DL_STYLE2)
        (void) qassociate(dsp->ds_wq, -1);

    /*
     * Re-initialize the DLPI state machine.
     */
    dsp->ds_dlstate = DL_UNATTACHED;
}

/*
 * This function is only called for VLAN streams. In raw mode, we strip VLAN
 * tags before sending packets up to the DLS clients, with the exception of
 * special priority tagged packets, in that case, we set the VID to 0.
 * mp must be a VLAN tagged packet.
 */
static mblk_t *
i_dld_ether_header_strip_tag(mblk_t *mp, boolean_t keep_pri)
{
    mblk_t *newmp;
    struct ether_vlan_header *evhp;
    uint16_t tci, new_tci;

    ASSERT(MBLKL(mp) >= sizeof (struct ether_vlan_header));
    if (DB_REF(mp) > 1) {
        newmp = copymsg(mp);
        if (newmp == NULL)
            return (NULL);
        freemsg(mp);
        mp = newmp;
    }
    evhp = (struct ether_vlan_header *)mp->b_rptr;

    tci = ntohs(evhp->ether_tci);
    if (VLAN_PRI(tci) == 0 || !keep_pri) {
        /*
         * Priority is 0, strip the tag.
         */
        ovbcopy(mp->b_rptr, mp->b_rptr + VLAN_TAGSZ, 2 * ETHERADDRL);
        mp->b_rptr += VLAN_TAGSZ;
    } else {
        /*
         * Priority is not 0, update the VID to 0.
         */
        new_tci = VLAN_TCI(VLAN_PRI(tci), VLAN_CFI(tci), VLAN_ID_NONE);
        evhp->ether_tci = htons(new_tci);
    }
    return (mp);
}

/*
 * Raw mode receive function.
 */
/*ARGSUSED*/
void
dld_str_rx_raw(void *arg, mac_resource_handle_t mrh, mblk_t *mp,
    mac_header_info_t *mhip)
{
    dld_str_t *dsp = (dld_str_t *)arg;
    boolean_t is_ethernet = (dsp->ds_mip->mi_media == DL_ETHER);
    mblk_t *next, *newmp;

    ASSERT(mp != NULL);
    do {
        /*
         * Get the pointer to the next packet in the chain and then
         * clear b_next before the packet gets passed on.
         */
        next = mp->b_next;
        mp->b_next = NULL;

        /*
         * Wind back b_rptr to point at the MAC header.
         */
        ASSERT(mp->b_rptr >= DB_BASE(mp) + mhip->mhi_hdrsize);
        mp->b_rptr -= mhip->mhi_hdrsize;

        /*
         * Certain MAC type plugins provide an illusion for raw
         * DLPI consumers.  They pretend that the MAC layer is
         * something that it's not for the benefit of observability
         * tools.  For example, mac_wifi pretends that it's Ethernet
         * for such consumers.  Here, unless native mode is enabled,
         * we call into the MAC layer so that this illusion can be
         * maintained.  The plugin will optionally transform the MAC
         * header here into something that can be passed up to raw
         * consumers.  The header goes from "cooked" mode to raw mode.
         */
        if (!dsp->ds_native) {
            newmp = mac_header_uncook(dsp->ds_mh, mp);
            if (newmp == NULL) {
                freemsg(mp);
                goto next;
            }
            mp = newmp;
        }

        /*
         * Strip the VLAN tag for VLAN streams.
         */
        if (is_ethernet &&
            mac_client_vid(dsp->ds_mch) != VLAN_ID_NONE) {
            /*
             * The priority should be kept only for VLAN
             * data-links.
             */
            newmp = i_dld_ether_header_strip_tag(mp,
                mac_client_is_vlan_vnic(dsp->ds_mch));
            if (newmp == NULL) {
                freemsg(mp);
                goto next;
            }
            mp = newmp;
        }

        /*
         * Pass the packet on.
         */
        if (canputnext(dsp->ds_rq))
            putnext(dsp->ds_rq, mp);
        else
            freemsg(mp);

next:
        /*
         * Move on to the next packet in the chain.
         */
        mp = next;
    } while (mp != NULL);
}

/*
 * Fast-path receive function.
 */
/*ARGSUSED*/
void
dld_str_rx_fastpath(void *arg, mac_resource_handle_t mrh, mblk_t *mp,
    mac_header_info_t *mhip)
{
    dld_str_t *dsp = (dld_str_t *)arg;
    mblk_t *next;
    size_t offset = 0;

    /*
     * MAC header stripping rules:
     *    - Tagged packets:
     *  a. VLAN streams. Strip the whole VLAN header including the tag.
     *  b. Physical streams
     *  - VLAN packets (non-zero VID). The stream must be either a
     *    DL_PROMISC_SAP listener or a ETHERTYPE_VLAN listener.
     *    Strip the Ethernet header but keep the VLAN header.
     *  - Special tagged packets (zero VID)
     *    * The stream is either a DL_PROMISC_SAP listener or a
     *      ETHERTYPE_VLAN listener, strip the Ethernet header but
     *      keep the VLAN header.
     *    * Otherwise, strip the whole VLAN header.
     *    - Untagged packets. Strip the whole MAC header.
     */
    if (mhip->mhi_istagged &&
        (mac_client_vid(dsp->ds_mch) == VLAN_ID_NONE) &&
        ((dsp->ds_sap == ETHERTYPE_VLAN) ||
        (dsp->ds_promisc & DLS_PROMISC_SAP))) {
        offset = VLAN_TAGSZ;
    }

    ASSERT(mp != NULL);
    do {
        /*
         * Get the pointer to the next packet in the chain and then
         * clear b_next before the packet gets passed on.
         */
        next = mp->b_next;
        mp->b_next = NULL;

        /*
         * Wind back b_rptr to point at the VLAN header.
         */
        ASSERT(mp->b_rptr >= DB_BASE(mp) + offset);
        mp->b_rptr -= offset;

        /*
         * Pass the packet on.
         */
        if (canputnext(dsp->ds_rq))
            putnext(dsp->ds_rq, mp);
        else
            freemsg(mp);
        /*
         * Move on to the next packet in the chain.
         */
        mp = next;
    } while (mp != NULL);
}

/*
 * Default receive function (send DL_UNITDATA_IND messages).
 */
/*ARGSUSED*/
void
dld_str_rx_unitdata(void *arg, mac_resource_handle_t mrh, mblk_t *mp,
    mac_header_info_t *mhip)
{
    dld_str_t       *dsp = (dld_str_t *)arg;
    mblk_t          *ud_mp;
    mblk_t          *next;
    size_t          offset = 0;
    boolean_t       strip_vlan = B_TRUE;

    /*
     * See MAC header stripping rules in the dld_str_rx_fastpath() function.
     */
    if (mhip->mhi_istagged &&
        (mac_client_vid(dsp->ds_mch) == VLAN_ID_NONE) &&
        ((dsp->ds_sap == ETHERTYPE_VLAN) ||
        (dsp->ds_promisc & DLS_PROMISC_SAP))) {
        offset = VLAN_TAGSZ;
        strip_vlan = B_FALSE;
    }

    ASSERT(mp != NULL);
    do {
        /*
         * Get the pointer to the next packet in the chain and then
         * clear b_next before the packet gets passed on.
         */
        next = mp->b_next;
        mp->b_next = NULL;

        /*
         * Wind back b_rptr to point at the MAC header.
         */
        ASSERT(mp->b_rptr >= DB_BASE(mp) + mhip->mhi_hdrsize);
        mp->b_rptr -= mhip->mhi_hdrsize;

        /*
         * Create the DL_UNITDATA_IND M_PROTO.
         */
        if ((ud_mp = str_unitdata_ind(dsp, mp, strip_vlan)) == NULL) {
            freemsgchain(mp);
            return;
        }

        /*
         * Advance b_rptr to point at the payload (or the VLAN header).
         */
        mp->b_rptr += (mhip->mhi_hdrsize - offset);

        /*
         * Prepend the DL_UNITDATA_IND.
         */
        ud_mp->b_cont = mp;

        /*
         * Send the message.
         */
        if (canputnext(dsp->ds_rq))
            putnext(dsp->ds_rq, ud_mp);
        else
            freemsg(ud_mp);

        /*
         * Move on to the next packet in the chain.
         */
        mp = next;
    } while (mp != NULL);
}

/*
 * DL_NOTIFY_IND: DL_NOTE_SDU_SIZE
 */
static void
str_notify_sdu_size(dld_str_t *dsp, uint_t max_sdu, uint_t multicast_sdu)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;

    if (!(dsp->ds_notifications & (DL_NOTE_SDU_SIZE|DL_NOTE_SDU_SIZE2)))
        return;

    if ((mp = mexchange(dsp->ds_wq, NULL, sizeof (dl_notify_ind_t),
        M_PROTO, 0)) == NULL)
        return;

    bzero(mp->b_rptr, sizeof (dl_notify_ind_t));
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    if (dsp->ds_notifications & DL_NOTE_SDU_SIZE2) {
        dlip->dl_notification = DL_NOTE_SDU_SIZE2;
        dlip->dl_data1 = max_sdu;
        dlip->dl_data2 = multicast_sdu;
    } else {
        dlip->dl_notification = DL_NOTE_SDU_SIZE;
        dlip->dl_data = max_sdu;
    }

    qreply(dsp->ds_wq, mp);
}

/*
 * Generate DL_NOTIFY_IND messages to notify the DLPI consumer of the
 * current state of the interface.
 */
void
dld_str_notify_ind(dld_str_t *dsp)
{
    mac_notify_type_t   type;

    for (type = 0; type < MAC_NNOTE; type++)
        str_notify(dsp, type);
}

typedef struct dl_unitdata_ind_wrapper {
    dl_unitdata_ind_t   dl_unitdata;
    uint8_t         dl_dest_addr[MAXMACADDRLEN + sizeof (uint16_t)];
    uint8_t         dl_src_addr[MAXMACADDRLEN + sizeof (uint16_t)];
} dl_unitdata_ind_wrapper_t;

/*
 * Create a DL_UNITDATA_IND M_PROTO message.
 */
static mblk_t *
str_unitdata_ind(dld_str_t *dsp, mblk_t *mp, boolean_t strip_vlan)
{
    mblk_t              *nmp;
    dl_unitdata_ind_wrapper_t   *dlwp;
    dl_unitdata_ind_t       *dlp;
    mac_header_info_t       mhi;
    uint_t              addr_length;
    uint8_t             *daddr;
    uint8_t             *saddr;

    /*
     * Get the packet header information.
     */
    if (mac_vlan_header_info(dsp->ds_mh, mp, &mhi) != 0)
        return (NULL);

    /*
     * Allocate a message large enough to contain the wrapper structure
     * defined above.
     */
    if ((nmp = mexchange(dsp->ds_wq, NULL,
        sizeof (dl_unitdata_ind_wrapper_t), M_PROTO,
        DL_UNITDATA_IND)) == NULL)
        return (NULL);

    dlwp = (dl_unitdata_ind_wrapper_t *)nmp->b_rptr;

    dlp = &(dlwp->dl_unitdata);
    ASSERT(dlp == (dl_unitdata_ind_t *)nmp->b_rptr);
    ASSERT(dlp->dl_primitive == DL_UNITDATA_IND);

    /*
     * Copy in the destination address.
     */
    addr_length = dsp->ds_mip->mi_addr_length;
    daddr = dlwp->dl_dest_addr;
    dlp->dl_dest_addr_offset = (uintptr_t)daddr - (uintptr_t)dlp;
    bcopy(mhi.mhi_daddr, daddr, addr_length);

    /*
     * Set the destination DLSAP to the SAP value encoded in the packet.
     */
    if (mhi.mhi_istagged && !strip_vlan)
        *(uint16_t *)(daddr + addr_length) = ETHERTYPE_VLAN;
    else
        *(uint16_t *)(daddr + addr_length) = mhi.mhi_bindsap;
    dlp->dl_dest_addr_length = addr_length + sizeof (uint16_t);

    /*
     * If the destination address was multicast or broadcast then the
     * dl_group_address field should be non-zero.
     */
    dlp->dl_group_address = (mhi.mhi_dsttype == MAC_ADDRTYPE_MULTICAST) ||
        (mhi.mhi_dsttype == MAC_ADDRTYPE_BROADCAST);

    /*
     * Copy in the source address if one exists.  Some MAC types (DL_IB
     * for example) may not have access to source information.
     */
    if (mhi.mhi_saddr == NULL) {
        dlp->dl_src_addr_offset = dlp->dl_src_addr_length = 0;
    } else {
        saddr = dlwp->dl_src_addr;
        dlp->dl_src_addr_offset = (uintptr_t)saddr - (uintptr_t)dlp;
        bcopy(mhi.mhi_saddr, saddr, addr_length);

        /*
         * Set the source DLSAP to the packet ethertype.
         */
        *(uint16_t *)(saddr + addr_length) = mhi.mhi_origsap;
        dlp->dl_src_addr_length = addr_length + sizeof (uint16_t);
    }

    return (nmp);
}

/*
 * DL_NOTIFY_IND: DL_NOTE_PROMISC_ON_PHYS
 */
static void
str_notify_promisc_on_phys(dld_str_t *dsp)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;

    if (!(dsp->ds_notifications & DL_NOTE_PROMISC_ON_PHYS))
        return;

    if ((mp = mexchange(dsp->ds_wq, NULL, sizeof (dl_notify_ind_t),
        M_PROTO, 0)) == NULL)
        return;

    bzero(mp->b_rptr, sizeof (dl_notify_ind_t));
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    dlip->dl_notification = DL_NOTE_PROMISC_ON_PHYS;

    qreply(dsp->ds_wq, mp);
}

/*
 * DL_NOTIFY_IND: DL_NOTE_PROMISC_OFF_PHYS
 */
static void
str_notify_promisc_off_phys(dld_str_t *dsp)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;

    if (!(dsp->ds_notifications & DL_NOTE_PROMISC_OFF_PHYS))
        return;

    if ((mp = mexchange(dsp->ds_wq, NULL, sizeof (dl_notify_ind_t),
        M_PROTO, 0)) == NULL)
        return;

    bzero(mp->b_rptr, sizeof (dl_notify_ind_t));
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    dlip->dl_notification = DL_NOTE_PROMISC_OFF_PHYS;

    qreply(dsp->ds_wq, mp);
}

/*
 * DL_NOTIFY_IND: DL_NOTE_PHYS_ADDR
 */
static void
str_notify_phys_addr(dld_str_t *dsp, uint_t addr_type, const uint8_t *addr)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;
    uint_t      addr_length;
    uint16_t    ethertype;

    if (!(dsp->ds_notifications & DL_NOTE_PHYS_ADDR))
        return;

    addr_length = dsp->ds_mip->mi_addr_length;
    if ((mp = mexchange(dsp->ds_wq, NULL,
        sizeof (dl_notify_ind_t) + addr_length + sizeof (uint16_t),
        M_PROTO, 0)) == NULL)
        return;

    bzero(mp->b_rptr, sizeof (dl_notify_ind_t));
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    dlip->dl_notification = DL_NOTE_PHYS_ADDR;
    dlip->dl_data = addr_type;
    dlip->dl_addr_offset = sizeof (dl_notify_ind_t);
    dlip->dl_addr_length = addr_length + sizeof (uint16_t);

    bcopy(addr, &dlip[1], addr_length);

    ethertype = (dsp->ds_sap < ETHERTYPE_802_MIN) ? 0 : dsp->ds_sap;
    *(uint16_t *)((uchar_t *)(dlip + 1) + addr_length) = ethertype;

    qreply(dsp->ds_wq, mp);
}

/*
 * DL_NOTIFY_IND: DL_NOTE_LINK_UP
 */
static void
str_notify_link_up(dld_str_t *dsp)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;

    if (!(dsp->ds_notifications & DL_NOTE_LINK_UP))
        return;

    if ((mp = mexchange(dsp->ds_wq, NULL, sizeof (dl_notify_ind_t),
        M_PROTO, 0)) == NULL)
        return;

    bzero(mp->b_rptr, sizeof (dl_notify_ind_t));
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    dlip->dl_notification = DL_NOTE_LINK_UP;

    qreply(dsp->ds_wq, mp);
}

/*
 * DL_NOTIFY_IND: DL_NOTE_LINK_DOWN
 */
static void
str_notify_link_down(dld_str_t *dsp)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;

    if (!(dsp->ds_notifications & DL_NOTE_LINK_DOWN))
        return;

    if ((mp = mexchange(dsp->ds_wq, NULL, sizeof (dl_notify_ind_t),
        M_PROTO, 0)) == NULL)
        return;

    bzero(mp->b_rptr, sizeof (dl_notify_ind_t));
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    dlip->dl_notification = DL_NOTE_LINK_DOWN;

    qreply(dsp->ds_wq, mp);
}

/*
 * DL_NOTIFY_IND: DL_NOTE_SPEED
 */
static void
str_notify_speed(dld_str_t *dsp, uint32_t speed)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;

    if (!(dsp->ds_notifications & DL_NOTE_SPEED))
        return;

    if ((mp = mexchange(dsp->ds_wq, NULL, sizeof (dl_notify_ind_t),
        M_PROTO, 0)) == NULL)
        return;

    bzero(mp->b_rptr, sizeof (dl_notify_ind_t));
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    dlip->dl_notification = DL_NOTE_SPEED;
    dlip->dl_data = speed;

    qreply(dsp->ds_wq, mp);
}

/*
 * DL_NOTIFY_IND: DL_NOTE_CAPAB_RENEG
 */
static void
str_notify_capab_reneg(dld_str_t *dsp)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;

    if (!(dsp->ds_notifications & DL_NOTE_CAPAB_RENEG))
        return;

    if ((mp = mexchange(dsp->ds_wq, NULL, sizeof (dl_notify_ind_t),
        M_PROTO, 0)) == NULL)
        return;

    bzero(mp->b_rptr, sizeof (dl_notify_ind_t));
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    dlip->dl_notification = DL_NOTE_CAPAB_RENEG;

    qreply(dsp->ds_wq, mp);
}

/*
 * DL_NOTIFY_IND: DL_NOTE_FASTPATH_FLUSH
 */
static void
str_notify_fastpath_flush(dld_str_t *dsp)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;

    if (!(dsp->ds_notifications & DL_NOTE_FASTPATH_FLUSH))
        return;

    if ((mp = mexchange(dsp->ds_wq, NULL, sizeof (dl_notify_ind_t),
        M_PROTO, 0)) == NULL)
        return;

    bzero(mp->b_rptr, sizeof (dl_notify_ind_t));
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    dlip->dl_notification = DL_NOTE_FASTPATH_FLUSH;

    qreply(dsp->ds_wq, mp);
}

static void
str_notify_allowed_ips(dld_str_t *dsp)
{
    mblk_t      *mp;
    dl_notify_ind_t *dlip;
    size_t      mp_size;
    mac_protect_t   *mrp;

    if (!(dsp->ds_notifications & DL_NOTE_ALLOWED_IPS))
        return;

    mp_size = sizeof (mac_protect_t) + sizeof (dl_notify_ind_t);
    if ((mp = mexchange(dsp->ds_wq, NULL, mp_size, M_PROTO, 0)) == NULL)
        return;

    mrp = mac_protect_get(dsp->ds_mh);
    bzero(mp->b_rptr, mp_size);
    dlip = (dl_notify_ind_t *)mp->b_rptr;
    dlip->dl_primitive = DL_NOTIFY_IND;
    dlip->dl_notification = DL_NOTE_ALLOWED_IPS;
    dlip->dl_data = 0;
    dlip->dl_addr_offset = sizeof (dl_notify_ind_t);
    dlip->dl_addr_length = sizeof (mac_protect_t);
    bcopy(mrp, mp->b_rptr + sizeof (dl_notify_ind_t),
        sizeof (mac_protect_t));

    qreply(dsp->ds_wq, mp);
}

/*
 * MAC notification callback.
 */
void
str_notify(void *arg, mac_notify_type_t type)
{
    dld_str_t       *dsp = (dld_str_t *)arg;
    queue_t         *q = dsp->ds_wq;
    mac_handle_t        mh = dsp->ds_mh;
    mac_client_handle_t mch = dsp->ds_mch;
    uint8_t         addr[MAXMACADDRLEN];

    switch (type) {
    case MAC_NOTE_TX:
        qenable(q);
        break;

    case MAC_NOTE_DEVPROMISC:
        /*
         * Send the appropriate DL_NOTIFY_IND.
         */
        if (mac_promisc_get(mh))
            str_notify_promisc_on_phys(dsp);
        else
            str_notify_promisc_off_phys(dsp);
        break;

    case MAC_NOTE_UNICST:
        /*
         * This notification is sent whenever the MAC unicast
         * address changes.
         */
        mac_unicast_primary_get(mh, addr);

        /*
         * Send the appropriate DL_NOTIFY_IND.
         */
        str_notify_phys_addr(dsp, DL_CURR_PHYS_ADDR, addr);
        break;

    case MAC_NOTE_DEST:
        /*
         * Only send up DL_NOTE_DEST_ADDR if the link has a
         * destination address.
         */
        if (mac_dst_get(dsp->ds_mh, addr))
            str_notify_phys_addr(dsp, DL_CURR_DEST_ADDR, addr);
        break;

    case MAC_NOTE_LOWLINK:
    case MAC_NOTE_LINK:
        /*
         * LOWLINK refers to the actual link status. For links that
         * are not part of a bridge instance LOWLINK and LINK state
         * are the same. But for a link part of a bridge instance
         * LINK state refers to the aggregate link status: "up" when
         * at least one link part of the bridge is up and is "down"
         * when all links part of the bridge are down.
         *
         * Clients can request to be notified of the LOWLINK state
         * using the DLIOCLOWLINK ioctl. Clients such as the bridge
         * daemon request lowlink state changes and upper layer clients
         * receive notifications of the aggregate link state changes
         * which is the default when requesting LINK UP/DOWN state
         * notifications.
         */

        /*
         * Check that the notification type matches the one that we
         * want.  If we want lower-level link notifications, and this
         * is upper, or if we want upper and this is lower, then
         * ignore.
         */
        if ((type == MAC_NOTE_LOWLINK) != dsp->ds_lowlink)
            break;
        /*
         * This notification is sent every time the MAC driver
         * updates the link state.
         */
        switch (mac_client_stat_get(mch, dsp->ds_lowlink ?
            MAC_STAT_LOWLINK_STATE : MAC_STAT_LINK_STATE)) {
        case LINK_STATE_UP: {
            uint64_t speed;
            /*
             * The link is up so send the appropriate
             * DL_NOTIFY_IND.
             */
            str_notify_link_up(dsp);

            speed = mac_stat_get(mh, MAC_STAT_IFSPEED);
            str_notify_speed(dsp, (uint32_t)(speed / 1000ull));
            break;
        }
        case LINK_STATE_DOWN:
            /*
             * The link is down so send the appropriate
             * DL_NOTIFY_IND.
             */
            str_notify_link_down(dsp);
            break;

        default:
            break;
        }
        break;

    case MAC_NOTE_CAPAB_CHG:
        /*
         * This notification is sent whenever the MAC resources
         * change or capabilities change. We need to renegotiate
         * the capabilities. Send the appropriate DL_NOTIFY_IND.
         */
        str_notify_capab_reneg(dsp);
        break;

    case MAC_NOTE_SDU_SIZE: {
        uint_t  max_sdu;
        uint_t  multicast_sdu;
        mac_sdu_get2(dsp->ds_mh, NULL, &max_sdu, &multicast_sdu);
        str_notify_sdu_size(dsp, max_sdu, multicast_sdu);
        break;
    }

    case MAC_NOTE_FASTPATH_FLUSH:
        str_notify_fastpath_flush(dsp);
        break;

    /* Unused notifications */
    case MAC_NOTE_MARGIN:
        break;

    case MAC_NOTE_ALLOWED_IPS:
        str_notify_allowed_ips(dsp);
        break;

    default:
        ASSERT(B_FALSE);
        break;
    }
}

/*
 * This function is called via a taskq mechansim to process all control
 * messages on a per 'dsp' end point.
 */
static void
dld_wput_nondata_task(void *arg)
{
    dld_str_t   *dsp = arg;
    mblk_t      *mp;

    mutex_enter(&dsp->ds_lock);
    while (dsp->ds_pending_head != NULL) {
        mp = dsp->ds_pending_head;
        dsp->ds_pending_head = mp->b_next;
        mp->b_next = NULL;
        if (dsp->ds_pending_head == NULL)
            dsp->ds_pending_tail = NULL;
        mutex_exit(&dsp->ds_lock);

        switch (DB_TYPE(mp)) {
        case M_PROTO:
        case M_PCPROTO:
            dld_proto(dsp, mp);
            break;
        case M_IOCTL:
            dld_ioc(dsp, mp);
            break;
        default:
            ASSERT(0);
        }

        mutex_enter(&dsp->ds_lock);
    }
    ASSERT(dsp->ds_pending_tail == NULL);
    dsp->ds_dlpi_pending = 0;
    cv_broadcast(&dsp->ds_dlpi_pending_cv);
    mutex_exit(&dsp->ds_lock);
}

/*
 * Kernel thread to handle taskq dispatch failures in dld_wput_data. This
 * thread is started at boot time.
 */
static void
dld_taskq_dispatch(void)
{
    callb_cpr_t cprinfo;
    dld_str_t   *dsp;

    CALLB_CPR_INIT(&cprinfo, &dld_taskq_lock, callb_generic_cpr,
        "dld_taskq_dispatch");
    mutex_enter(&dld_taskq_lock);

    while (!dld_taskq_quit) {
        dsp = list_head(&dld_taskq_list);
        while (dsp != NULL) {
            list_remove(&dld_taskq_list, dsp);
            mutex_exit(&dld_taskq_lock);
            VERIFY(taskq_dispatch(dld_taskq, dld_wput_nondata_task,
                dsp, TQ_SLEEP) != 0);
            mutex_enter(&dld_taskq_lock);
            dsp = list_head(&dld_taskq_list);
        }

        CALLB_CPR_SAFE_BEGIN(&cprinfo);
        cv_wait(&dld_taskq_cv, &dld_taskq_lock);
        CALLB_CPR_SAFE_END(&cprinfo, &dld_taskq_lock);
    }

    dld_taskq_done = B_TRUE;
    cv_signal(&dld_taskq_cv);
    CALLB_CPR_EXIT(&cprinfo);
    thread_exit();
}

/*
 * All control operations are serialized on the 'dsp' and are also funneled
 * through a taskq mechanism to ensure that subsequent processing has kernel
 * context and can safely use cv_wait.
 *
 * Mechanisms to handle taskq dispatch failures
 *
 * The only way to be sure that taskq dispatch does not fail is to either
 * specify TQ_SLEEP or to use a static taskq and prepopulate it with
 * some number of entries and make sure that the number of outstanding requests
 * are less than that number. We can't use TQ_SLEEP since we don't know the
 * context. Nor can we bound the total number of 'dsp' end points. So we are
 * unable to use either of the above schemes, and are forced to deal with
 * taskq dispatch failures. Note that even dynamic taskq could fail in
 * dispatch if TQ_NOSLEEP is specified, since this flag is translated
 * eventually to KM_NOSLEEP and kmem allocations could fail in the taskq
 * framework.
 *
 * We maintain a queue of 'dsp's that encountered taskq dispatch failure.
 * We also have a single global thread to retry the taskq dispatch. This
 * thread loops in 'dld_taskq_dispatch' and retries the taskq dispatch, but
 * uses TQ_SLEEP to ensure eventual success of the dispatch operation.
 */
static void
dld_wput_nondata(dld_str_t *dsp, mblk_t *mp)
{
    ASSERT(mp->b_next == NULL);
    mutex_enter(&dsp->ds_lock);
    if (dsp->ds_pending_head != NULL) {
        ASSERT(dsp->ds_dlpi_pending);
        dsp->ds_pending_tail->b_next = mp;
        dsp->ds_pending_tail = mp;
        mutex_exit(&dsp->ds_lock);
        return;
    }
    ASSERT(dsp->ds_pending_tail == NULL);
    dsp->ds_pending_head = dsp->ds_pending_tail = mp;
    /*
     * At this point if ds_dlpi_pending is set, it implies that the taskq
     * thread is still active and is processing the last message, though
     * the pending queue has been emptied.
     */
    if (dsp->ds_dlpi_pending) {
        mutex_exit(&dsp->ds_lock);
        return;
    }

    dsp->ds_dlpi_pending = 1;
    mutex_exit(&dsp->ds_lock);

    if (taskq_dispatch(dld_taskq, dld_wput_nondata_task, dsp,
        TQ_NOSLEEP) != 0)
        return;

    mutex_enter(&dld_taskq_lock);
    list_insert_tail(&dld_taskq_list, dsp);
    cv_signal(&dld_taskq_cv);
    mutex_exit(&dld_taskq_lock);
}

/*
 * Process an M_IOCTL message.
 */
static void
dld_ioc(dld_str_t *dsp, mblk_t *mp)
{
    uint_t          cmd;

    cmd = ((struct iocblk *)mp->b_rptr)->ioc_cmd;
    ASSERT(dsp->ds_type == DLD_DLPI);

    switch (cmd) {
    case DLIOCNATIVE:
        ioc_native(dsp, mp);
        break;
    case DLIOCMARGININFO:
        ioc_margin(dsp, mp);
        break;
    case DLIOCRAW:
        ioc_raw(dsp, mp);
        break;
    case DLIOCHDRINFO:
        ioc_fast(dsp, mp);
        break;
    case DLIOCLOWLINK:
        ioc_lowlink(dsp, mp);
        break;
    default:
        ioc(dsp, mp);
    }
}

/*
 * DLIOCNATIVE
 */
static void
ioc_native(dld_str_t *dsp, mblk_t *mp)
{
    queue_t *q = dsp->ds_wq;
    const mac_info_t *mip = dsp->ds_mip;

    /*
     * Native mode can be enabled if it's disabled and if the
     * native media type is different.
     */
    if (!dsp->ds_native && mip->mi_media != mip->mi_nativemedia)
        dsp->ds_native = B_TRUE;

    if (dsp->ds_native)
        miocack(q, mp, 0, mip->mi_nativemedia);
    else
        miocnak(q, mp, 0, ENOTSUP);
}

/*
 * DLIOCMARGININFO
 */
static void
ioc_margin(dld_str_t *dsp, mblk_t *mp)
{
    queue_t *q = dsp->ds_wq;
    uint32_t margin;
    int err;

    if (dsp->ds_dlstate == DL_UNATTACHED) {
        err = EINVAL;
        goto failed;
    }
    if ((err = miocpullup(mp, sizeof (uint32_t))) != 0)
        goto failed;

    mac_margin_get(dsp->ds_mh, &margin);
    *((uint32_t *)mp->b_cont->b_rptr) = margin;
    miocack(q, mp, sizeof (uint32_t), 0);
    return;

failed:
    miocnak(q, mp, 0, err);
}

/*
 * DLIOCRAW
 */
static void
ioc_raw(dld_str_t *dsp, mblk_t *mp)
{
    queue_t *q = dsp->ds_wq;
    mac_perim_handle_t  mph;

    if (dsp->ds_mh == NULL) {
        dsp->ds_mode = DLD_RAW;
        miocack(q, mp, 0, 0);
        return;
    }

    mac_perim_enter_by_mh(dsp->ds_mh, &mph);
    if (dsp->ds_polling || dsp->ds_direct) {
        mac_perim_exit(mph);
        miocnak(q, mp, 0, EPROTO);
        return;
    }

    if (dsp->ds_mode != DLD_RAW && dsp->ds_dlstate == DL_IDLE) {
        /*
         * Set the receive callback.
         */
        dls_rx_set(dsp, dld_str_rx_raw, dsp);
    }

    /*
     * Note that raw mode is enabled.
     */
    dsp->ds_mode = DLD_RAW;
    mac_perim_exit(mph);

    miocack(q, mp, 0, 0);
}

/*
 * DLIOCHDRINFO
 */
static void
ioc_fast(dld_str_t *dsp, mblk_t *mp)
{
    dl_unitdata_req_t *dlp;
    off_t       off;
    size_t      len;
    const uint8_t   *addr;
    uint16_t    sap;
    mblk_t      *nmp;
    mblk_t      *hmp;
    uint_t      addr_length;
    queue_t     *q = dsp->ds_wq;
    int     err;
    mac_perim_handle_t  mph;

    if (dld_opt & DLD_OPT_NO_FASTPATH) {
        err = ENOTSUP;
        goto failed;
    }

    /*
     * DLIOCHDRINFO should only come from IP. The one initiated from
     * user-land should not be allowed.
     */
    if (((struct iocblk *)mp->b_rptr)->ioc_cr != kcred) {
        err = EINVAL;
        goto failed;
    }

    nmp = mp->b_cont;
    if (nmp == NULL || MBLKL(nmp) < sizeof (dl_unitdata_req_t) ||
        (dlp = (dl_unitdata_req_t *)nmp->b_rptr,
        dlp->dl_primitive != DL_UNITDATA_REQ)) {
        err = EINVAL;
        goto failed;
    }

    off = dlp->dl_dest_addr_offset;
    len = dlp->dl_dest_addr_length;

    if (!MBLKIN(nmp, off, len)) {
        err = EINVAL;
        goto failed;
    }

    if (dsp->ds_dlstate != DL_IDLE) {
        err = ENOTSUP;
        goto failed;
    }

    addr_length = dsp->ds_mip->mi_addr_length;
    if (len != addr_length + sizeof (uint16_t)) {
        err = EINVAL;
        goto failed;
    }

    addr = nmp->b_rptr + off;
    sap = *(uint16_t *)(nmp->b_rptr + off + addr_length);

    if ((hmp = dls_header(dsp, addr, sap, 0, NULL)) == NULL) {
        err = ENOMEM;
        goto failed;
    }

    /*
     * This ioctl might happen concurrently with a direct call to dld_capab
     * that tries to enable direct and/or poll capabilities. Since the
     * stack does not serialize them, we do so here to avoid mixing
     * the callbacks.
     */
    mac_perim_enter_by_mh(dsp->ds_mh, &mph);
    if (dsp->ds_mode != DLD_FASTPATH) {
        /*
         * Set the receive callback (unless polling is enabled).
         */
        if (!dsp->ds_polling && !dsp->ds_direct)
            dls_rx_set(dsp, dld_str_rx_fastpath, dsp);

        /*
         * Note that fast-path mode is enabled.
         */
        dsp->ds_mode = DLD_FASTPATH;
    }
    mac_perim_exit(mph);

    freemsg(nmp->b_cont);
    nmp->b_cont = hmp;

    miocack(q, mp, MBLKL(nmp) + MBLKL(hmp), 0);
    return;
failed:
    miocnak(q, mp, 0, err);
}

/*
 * DLIOCLOWLINK: request actual link state changes. When the
 * link is part of a bridge instance the client receives actual
 * link state changes and not the aggregate link status. Used by
 * the bridging daemon (bridged) for proper RSTP operation.
 */
static void
ioc_lowlink(dld_str_t *dsp, mblk_t *mp)
{
    queue_t *q = dsp->ds_wq;
    int err;

    if ((err = miocpullup(mp, sizeof (int))) != 0) {
        miocnak(q, mp, 0, err);
    } else {
        /* LINTED: alignment */
        dsp->ds_lowlink = *(boolean_t *)mp->b_cont->b_rptr;
        miocack(q, mp, 0, 0);
    }
}

/*
 * Catch-all handler.
 */
static void
ioc(dld_str_t *dsp, mblk_t *mp)
{
    queue_t *q = dsp->ds_wq;

    if (dsp->ds_dlstate == DL_UNATTACHED) {
        miocnak(q, mp, 0, EINVAL);
        return;
    }
    mac_ioctl(dsp->ds_mh, q, mp);
}