source: vbox/trunk/src/VBox/HostDrivers/VBoxNetFlt/solaris/VBoxNetFlt-solaris.c@ 13875

/* $Id: VBoxNetFlt-solaris.c 13875 2008-11-05 15:07:37Z vboxsync $ */
/** @file
 * VBoxNetFlt - Network Filter Driver (Host), Solaris Specific Code.
 */

/*
 * Copyright (C) 2008 Sun Microsystems, Inc.
 *
 * Sun Microsystems, Inc. confidential
 * All rights reserved
 */

/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/
#if defined(DEBUG_ramshankar) && !defined(LOG_ENABLED)
# define LOG_ENABLED
#endif
#define LOG_GROUP LOG_GROUP_NET_FLT_DRV
#include <VBox/log.h>
#include <VBox/err.h>
#include <VBox/cdefs.h>
#include <VBox/version.h>
#include <iprt/string.h>
#include <iprt/initterm.h>
#include <iprt/assert.h>
#include <iprt/alloca.h>
#include <iprt/net.h>
#include <iprt/mem.h>
#include <iprt/thread.h>
#include <iprt/spinlock.h>
#include <iprt/crc32.h>

#include <inet/ip.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/kstr.h>
#include <sys/file.h>
#include <sys/sockio.h>
#include <sys/strsubr.h>
#include <sys/pathname.h>
#include <sys/t_kuser.h>

#include <sys/types.h>
#include <sys/dlpi.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/ethernet.h>
#include <sys/stat.h>
#include <sys/stream.h>
#include <sys/stropts.h>
#include <sys/strsun.h>
#include <sys/modctl.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/sunldi.h>

/*
 * Experimental: Using netinfo interfaces and queuing out packets.
 * This is for playing better with IPFilter.
 */
#undef VBOXNETFLT_SOLARIS_USE_NETINFO
#ifdef VBOXNETFLT_SOLARIS_USE_NETINFO
# include <sys/neti.h>
#endif

// Workaround for very strange define in sys/user.h
// #define u       (curproc->p_user)       /* user is now part of proc structure */
#ifdef u
#undef u
#endif

#define VBOXNETFLT_OS_SPECFIC 1
#include "../VBoxNetFltInternal.h"

/*******************************************************************************
*   Defined Constants And Macros                                               *
*******************************************************************************/
#define VBOXSOLQUOTE2(x)         #x
#define VBOXSOLQUOTE(x)          VBOXSOLQUOTE2(x)
/** The module name. */
#define DEVICE_NAME              "vboxflt"
/** The module descriptions as seen in 'modinfo'. */
#define DEVICE_DESC_DRV          "VirtualBox NetDrv"
#define DEVICE_DESC_MOD          "VirtualBox NetMod"

/** @todo Remove the below hackery once done! */
#if defined(DEBUG_ramshankar) && defined(LOG_ENABLED)
# undef Log
# define Log        LogRel
# undef LogFlow
# define LogFlow    LogRel
#endif

/** Maximum loopback packet queue size per interface */
#define VBOXNETFLT_LOOPBACK_SIZE        32

/*******************************************************************************
*   Global Functions                                                           *
*******************************************************************************/
/**
 * Stream Driver hooks.
 */
static int VBoxNetFltSolarisGetInfo(dev_info_t *pDip, ddi_info_cmd_t enmCmd, void *pArg, void **ppResult);
static int VBoxNetFltSolarisAttach(dev_info_t *pDip, ddi_attach_cmd_t enmCmd);
static int VBoxNetFltSolarisDetach(dev_info_t *pDip, ddi_detach_cmd_t enmCmd);

/**
 * Stream Module hooks.
 */
static int VBoxNetFltSolarisModOpen(queue_t *pQueue, dev_t *pDev, int fFile, int fStream, cred_t *pCred);
static int VBoxNetFltSolarisModClose(queue_t *pQueue, int fFile, cred_t *pCred);
static int VBoxNetFltSolarisModReadPut(queue_t *pQueue, mblk_t *pMsg);
static int VBoxNetFltSolarisModWritePut(queue_t *pQueue, mblk_t *pMsg);

/**
 * OS specific hooks invoked from common VBoxNetFlt ring-0.
 */
bool vboxNetFltPortOsIsPromiscuous(PVBOXNETFLTINS pThis);
void vboxNetFltPortOsGetMacAddress(PVBOXNETFLTINS pThis, PRTMAC pMac);
bool vboxNetFltPortOsIsHostMac(PVBOXNETFLTINS pThis, PCRTMAC pMac);
void vboxNetFltPortOsSetActive(PVBOXNETFLTINS pThis, bool fActive);
int vboxNetFltOsDisconnectIt(PVBOXNETFLTINS pThis);
int vboxNetFltOsConnectIt(PVBOXNETFLTINS pThis);
void vboxNetFltOsDeleteInstance(PVBOXNETFLTINS pThis);
int vboxNetFltOsInitInstance(PVBOXNETFLTINS pThis);
int vboxNetFltOsPreInitInstance(PVBOXNETFLTINS pThis);


/*******************************************************************************
*   Structures and Typedefs                                                    *
*******************************************************************************/
/**
 * Streams: module info.
 */
static struct module_info g_VBoxNetFltSolarisModInfo =
{
    0xbad,                          /* module id */
    DEVICE_NAME,
    0,                              /* min. packet size */
    INFPSZ,                         /* max. packet size */
    0,                              /* hi-water mask */
    0                               /* lo-water mask */
};

/**
 * Streams: read queue hooks.
 */
static struct qinit g_VBoxNetFltSolarisReadQ =
{
    VBoxNetFltSolarisModReadPut,
    NULL,                           /* service */
    VBoxNetFltSolarisModOpen,
    VBoxNetFltSolarisModClose,
    NULL,                           /* admin (reserved) */
    &g_VBoxNetFltSolarisModInfo,
    NULL                            /* module stats */
};

/**
 * Streams: write queue hooks.
 */
static struct qinit g_VBoxNetFltSolarisWriteQ =
{
    VBoxNetFltSolarisModWritePut,
    NULL,                           /* service */
    NULL,                           /* open */
    NULL,                           /* close */
    NULL,                           /* admin (reserved) */
    &g_VBoxNetFltSolarisModInfo,
    NULL                            /* module stats */
};

/**
 * Streams: IO stream tab.
 */
static struct streamtab g_VBoxNetFltSolarisStreamTab =
{
    &g_VBoxNetFltSolarisReadQ,
    &g_VBoxNetFltSolarisWriteQ,
    NULL,                           /* muxread init */
    NULL                            /* muxwrite init */
};

/**
 * cb_ops: driver char/block entry points
 */
static struct cb_ops g_VBoxNetFltSolarisCbOps =
{
    nulldev,                        /* cb open */
    nulldev,                        /* cb close */
    nodev,                          /* b strategy */
    nodev,                          /* b dump */
    nodev,                          /* b print */
    nodev,                          /* cb read */
    nodev,                          /* cb write */
    nodev,                          /* cb ioctl */
    nodev,                          /* c devmap */
    nodev,                          /* c mmap */
    nodev,                          /* c segmap */
    nochpoll,                       /* c poll */
    ddi_prop_op,                    /* property ops */
    &g_VBoxNetFltSolarisStreamTab,
    D_NEW | D_MP | D_MTQPAIR,       /* compat. flag */
    CB_REV                          /* revision */
};

/**
 * dev_ops: driver entry/exit and other ops.
 */
static struct dev_ops g_VBoxNetFltSolarisDevOps =
{
    DEVO_REV,                       /* driver build revision */
    0,                              /* ref count */
    VBoxNetFltSolarisGetInfo,
    nulldev,                        /* identify */
    nulldev,                        /* probe */
    VBoxNetFltSolarisAttach,
    VBoxNetFltSolarisDetach,
    nodev,                          /* reset */
    &g_VBoxNetFltSolarisCbOps,
    (struct bus_ops *)0,
    nodev                           /* power */
};

/**
 * modldrv: export driver specifics to kernel
 */
static struct modldrv g_VBoxNetFltSolarisDriver =
{
    &mod_driverops,                 /* extern from kernel */
    DEVICE_DESC_DRV " " VBOX_VERSION_STRING "r" VBOXSOLQUOTE(VBOX_SVN_REV),
    &g_VBoxNetFltSolarisDevOps
};

/**
 * fmodsw: streams module ops
 */
static struct fmodsw g_VBoxNetFltSolarisModOps =
{
    DEVICE_NAME,
    &g_VBoxNetFltSolarisStreamTab,
    D_NEW | D_MP | D_MTQPAIR
};

/**
 * modlstrmod: streams module specifics to kernel
 */
static struct modlstrmod g_VBoxNetFltSolarisModule =
{
    &mod_strmodops,                 /* extern from kernel */
    DEVICE_DESC_MOD " " VBOX_VERSION_STRING "r" VBOXSOLQUOTE(VBOX_SVN_REV),
    &g_VBoxNetFltSolarisModOps
};

/**
 * modlinkage: export install/remove/info to the kernel
 */
static struct modlinkage g_VBoxNetFltSolarisModLinkage =
{
    MODREV_1,                       /* loadable module system revision */
    &g_VBoxNetFltSolarisDriver,     /* streams driver framework */
    &g_VBoxNetFltSolarisModule,     /* streams module framework */
    NULL                            /* terminate array of linkage structures */
};

struct vboxnetflt_state_t;

/**
 * vboxnetflt_dladdr_t: DL SAP address format
 */
typedef struct vboxnetflt_dladdr_t
{
    ether_addr_t Mac;
    uint16_t SAP;
} vboxnetflt_dladdr_t;

#define VBOXNETFLT_DLADDRL        sizeof(vboxnetflt_dladdr_t)

/**
 * which stream is this?
 */
typedef enum VBOXNETFLTSTREAMTYPE
{
    kUndefined = 0,
    kIp4Stream = 0x1b,
    kIp6Stream = 0xcc,
    kArpStream = 0xab,
    kPromiscStream = 0xdf
} VBOXNETFLTSTREAMTYPE;

/**
 * loopback packet identifier
 */
typedef struct VBOXNETFLTPACKETID
{
    struct VBOXNETFLTPACKETID *pNext;
    uint16_t cbPacket;
    uint16_t Checksum;
    RTMAC SrcMac;
    RTMAC DstMac;
} VBOXNETFLTPACKETID;
typedef struct VBOXNETFLTPACKETID *PVBOXNETFLTPACKETID;

/**
 * vboxnetflt_stream_t: per-stream data (multiple streams per interface)
 */
typedef struct vboxnetflt_stream_t
{
    int DevMinor;                         /* minor device no. (for clone) */
    queue_t *pReadQueue;                  /* read side queue */
    struct vboxnetflt_stream_t *pNext;    /* next stream in list */
    PVBOXNETFLTINS volatile pThis;        /* the backend instance */
    VBOXNETFLTSTREAMTYPE Type;            /* the type of the stream */
} vboxnetflt_stream_t;

/**
 * vboxnetflt_promisc_stream_t: per-interface dedicated stream data
 */
typedef struct vboxnetflt_promisc_stream_t
{
    vboxnetflt_stream_t Stream;           /* The generic stream */
    bool fPromisc;                        /* cached promiscous value */
    bool fRawMode;                        /* whether raw mode request was successful */
    uint32_t ModeReqId;                   /* track MIOCTLs for swallowing our fake request acknowledgements */
    size_t cLoopback;                     /* loopback queue size list */
    PVBOXNETFLTPACKETID pHead;            /* loopback packet identifier head */
    PVBOXNETFLTPACKETID pTail;            /* loopback packet identifier tail */
} vboxnetflt_promisc_stream_t;


/*******************************************************************************
*   Internal Functions                                                           *
*******************************************************************************/
static int vboxNetFltSolarisSetRawMode(vboxnetflt_promisc_stream_t *pPromiscStream);
/* static int vboxNetFltSolarisSetFastMode(queue_t *pQueue); */

static int vboxNetFltSolarisPhysAddrReq(queue_t *pQueue);
static void vboxNetFltSolarisCachePhysAddr(PVBOXNETFLTINS pThis, mblk_t *pPhysAddrAckMsg);
static int vboxNetFltSolarisBindReq(queue_t *pQueue, int SAP);
static int vboxNetFltSolarisNotifyReq(queue_t *pQueue);

static int vboxNetFltSolarisUnitDataToRaw(PVBOXNETFLTINS pThis, mblk_t *pMsg, mblk_t **ppRawMsg);
static int vboxNetFltSolarisRawToUnitData(mblk_t *pMsg, mblk_t **ppDlpiMsg);

static inline void vboxNetFltSolarisInitPacketId(PVBOXNETFLTPACKETID pTag, mblk_t *pMsg);
static int vboxNetFltSolarisQueueLoopback(PVBOXNETFLTINS pThis, vboxnetflt_promisc_stream_t *pPromiscStream, mblk_t *pMsg);
static bool vboxNetFltSolarisIsOurMBlk(PVBOXNETFLTINS pThis, vboxnetflt_promisc_stream_t *pPromiscStream, mblk_t *pMsg);

static mblk_t *vboxNetFltSolarisMBlkFromSG(PVBOXNETFLTINS pThis, PINTNETSG pSG, uint32_t fDst);
static unsigned vboxNetFltSolarisMBlkCalcSGSegs(PVBOXNETFLTINS pThis, mblk_t *pMsg);
static int vboxNetFltSolarisMBlkToSG(PVBOXNETFLTINS pThis, mblk_t *pMsg, PINTNETSG pSG, unsigned cSegs, uint32_t fSrc);
static int vboxNetFltSolarisRecv(PVBOXNETFLTINS pThis, vboxnetflt_stream_t *pStream, queue_t *pQueue, mblk_t *pMsg);
static PVBOXNETFLTINS vboxNetFltSolarisFindInstance(vboxnetflt_stream_t *pStream);
static mblk_t *vboxNetFltSolarisFixChecksums(mblk_t *pMsg);
static void vboxNetFltSolarisAnalyzeMBlk(mblk_t *pMsg);


/*******************************************************************************
*   Global Variables                                                           *
*******************************************************************************/
/** Global device info handle. */
static dev_info_t *g_pVBoxNetFltSolarisDip = NULL;

/** The (common) global data. */
static VBOXNETFLTGLOBALS g_VBoxNetFltSolarisGlobals;

/** The list of all opened streams. */
vboxnetflt_stream_t *g_VBoxNetFltSolarisStreams;

/**
 * g_VBoxNetFltInstance is the current PVBOXNETFLTINS to be associated with the stream being created
 * in ModOpen. This is just shared global data between the dynamic attach and the ModOpen procedure.
 */
PVBOXNETFLTINS volatile g_VBoxNetFltSolarisInstance;

/** Goes along with the instance to determine type of stream being opened/created. */
VBOXNETFLTSTREAMTYPE volatile g_VBoxNetFltSolarisStreamType;

/** GCC C++ hack. */
unsigned __gxx_personality_v0 = 0xdecea5ed;


/**
 * Kernel entry points
 */
int _init(void)
{
    LogFlow((DEVICE_NAME ":_init\n"));

    /*
     * Prevent module autounloading.
     */
    modctl_t *pModCtl = mod_getctl(&g_VBoxNetFltSolarisModLinkage);
    if (pModCtl)
        pModCtl->mod_loadflags |= MOD_NOAUTOUNLOAD;
    else
        LogRel((DEVICE_NAME ":failed to disable autounloading!\n"));

    /*
     * Initialize IPRT.
     */
    int rc = RTR0Init(0);
    if (RT_SUCCESS(rc))
    {
        /*
         * Initialize Solaris specific globals here.
         */
        g_VBoxNetFltSolarisStreams = NULL;
        g_VBoxNetFltSolarisInstance = NULL;

        /*
         * Initialize the globals and connect to the support driver.
         *
         * This will call back vboxNetFltOsOpenSupDrv (and maybe vboxNetFltOsCloseSupDrv)
         * for establishing the connect to the support driver.
         */
        memset(&g_VBoxNetFltSolarisGlobals, 0, sizeof(g_VBoxNetFltSolarisGlobals));
        rc = vboxNetFltInitGlobals(&g_VBoxNetFltSolarisGlobals);
        if (RT_SUCCESS(rc))
        {
            rc = mod_install(&g_VBoxNetFltSolarisModLinkage);
            if (!rc)
                return rc;

            LogRel((DEVICE_NAME ":mod_install failed. rc=%d\n", rc));
            vboxNetFltTryDeleteGlobals(&g_VBoxNetFltSolarisGlobals);
        }
        else
            LogRel((DEVICE_NAME ":failed to initialize globals.\n"));

        RTR0Term();
    }
    else
        LogRel((DEVICE_NAME ":failed to initialize IPRT (rc=%d)\n", rc));

    memset(&g_VBoxNetFltSolarisGlobals, 0, sizeof(g_VBoxNetFltSolarisGlobals));
    return -1;
}


int _fini(void)
{
    int rc;
    LogFlow((DEVICE_NAME ":_fini\n"));

    /*
     * Undo the work done during start (in reverse order).
     */
    rc = vboxNetFltTryDeleteGlobals(&g_VBoxNetFltSolarisGlobals);
    if (RT_FAILURE(rc))
    {
        LogRel((DEVICE_NAME ":_fini - busy!\n"));
        return EBUSY;
    }

    RTR0Term();

    return mod_remove(&g_VBoxNetFltSolarisModLinkage);
}


int _info(struct modinfo *pModInfo)
{
    LogFlow((DEVICE_NAME ":_info\n"));

    int rc = mod_info(&g_VBoxNetFltSolarisModLinkage, pModInfo);

    LogFlow((DEVICE_NAME ":_info returns %d\n", rc));
    return rc;
}


/**
 * Attach entry point, to attach a device to the system or resume it.
 *
 * @param   pDip            The module structure instance.
 * @param   enmCmd          Operation type (attach/resume).
 *
 * @returns corresponding solaris error code.
 */
static int VBoxNetFltSolarisAttach(dev_info_t *pDip, ddi_attach_cmd_t enmCmd)
{
    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisAttach pDip=%p enmCmd=%d\n", pDip, enmCmd));

    switch (enmCmd)
    {
        case DDI_ATTACH:
        {
            int instance = ddi_get_instance(pDip);
            int rc = ddi_create_minor_node(pDip, DEVICE_NAME, S_IFCHR, instance, DDI_PSEUDO, CLONE_DEV);
            if (rc == DDI_SUCCESS)
            {
                g_pVBoxNetFltSolarisDip = pDip;
                ddi_report_dev(pDip);
                return DDI_SUCCESS;
            }
            else
                LogRel((DEVICE_NAME ":VBoxNetFltSolarisAttach failed to create minor node. rc%d\n", rc));
            return DDI_FAILURE;
        }

        case DDI_RESUME:
        {
            /* Nothing to do here... */
            return DDI_SUCCESS;
        }
    }
    return DDI_FAILURE;
}


/**
 * Detach entry point, to detach a device to the system or suspend it.
 *
 * @param   pDip            The module structure instance.
 * @param   enmCmd          Operation type (detach/suspend).
 *
 * @returns corresponding solaris error code.
 */
static int VBoxNetFltSolarisDetach(dev_info_t *pDip, ddi_detach_cmd_t enmCmd)
{
    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisDetach pDip=%p enmCmd=%d\n", pDip, enmCmd));

    switch (enmCmd)
    {
        case DDI_DETACH:
        {
            int instance = ddi_get_instance(pDip);
            ddi_remove_minor_node(pDip, NULL);
            return DDI_SUCCESS;
        }

        case DDI_RESUME:
        {
            /* Nothing to do here... */
            return DDI_SUCCESS;
        }
    }
    return DDI_FAILURE;
}


/**
 * Info entry point, called by solaris kernel for obtaining driver info.
 *
 * @param   pDip            The module structure instance (do not use).
 * @param   enmCmd          Information request type.
 * @param   pvArg           Type specific argument.
 * @param   ppvResult       Where to store the requested info.
 *
 * @returns  corresponding solaris error code.
 */
static int VBoxNetFltSolarisGetInfo(dev_info_t *pDip, ddi_info_cmd_t enmCmd, void *pvArg, void **ppResult)
{
    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisGetInfo pDip=%p enmCmd=%d pArg=%p instance=%d\n", pDip, enmCmd,
                getminor((dev_t)pvArg)));

    switch (enmCmd)
    {
        case DDI_INFO_DEVT2DEVINFO:
        {
            *ppResult = g_pVBoxNetFltSolarisDip;
            return DDI_SUCCESS;
        }

        case DDI_INFO_DEVT2INSTANCE:
        {
            int instance = getminor((dev_t)pvArg);
            *ppResult = (void *)(uintptr_t)instance;
            return DDI_SUCCESS;
        }
    }

    return DDI_FAILURE;
}


/**
 * Stream module open entry point, initializes the queue and allows streams processing.
 *
 * @param   pQueue          Pointer to the queue (cannot be NULL).
 * @param   pDev            Pointer to the dev_t associated with the driver at the end of the stream.
 * @param   fOpenMode       Open mode (always 0 for streams driver, thus ignored).
 * @param   fStreamMode     Stream open mode.
 * @param   pCred           Pointer to user credentials.
 *
 * @returns corresponding solaris error code.
 */
static int VBoxNetFltSolarisModOpen(queue_t *pQueue, dev_t *pDev, int fOpenMode, int fStreamMode, cred_t *pCred)
{
    Assert(pQueue);

    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModOpen pQueue=%p pDev=%p fOpenMode=%d fStreamMode=%d\n", pQueue, pDev,
            fOpenMode, fStreamMode));

    /*
     * Already open?
     */
    if (pQueue->q_ptr)
    {
        LogRel((DEVICE_NAME ":VBoxNetFltSolarisModOpen invalid open.\n"));
        return ENOENT;
    }

    /*
     * Check for the VirtualBox instance.
     */
    PVBOXNETFLTINS pThis = g_VBoxNetFltSolarisInstance;
    if (!pThis)
    {
        LogRel((DEVICE_NAME ":VBoxNetFltSolarisModOpen failed to get VirtualBox instance.\n"));
        return ENOENT;
    }

    /*
     * Check VirtualBox stream type.
     */
    if (g_VBoxNetFltSolarisStreamType == kUndefined)
    {
        LogRel((DEVICE_NAME ":VBoxNetFltSolarisModOpen failed due to undefined VirtualBox open mode.\n"));
        return ENOENT;
    }

    /*
     * Get minor number. For clone opens provide a new dev_t.
     */
    minor_t DevMinor = 0;
    vboxnetflt_stream_t *pStream = NULL;
    vboxnetflt_stream_t **ppPrevStream = &g_VBoxNetFltSolarisStreams;
    if (fStreamMode == CLONEOPEN)
    {
        for (; (pStream = *ppPrevStream) != NULL; ppPrevStream = &pStream->pNext)
        {
            if (DevMinor < pStream->DevMinor)
                break;
            DevMinor++;
        }
        *pDev = makedevice(getmajor(*pDev), DevMinor);
    }
    else
        DevMinor = getminor(*pDev);

    if (g_VBoxNetFltSolarisStreamType == kPromiscStream)
    {
        vboxnetflt_promisc_stream_t *pPromiscStream = RTMemAlloc(sizeof(vboxnetflt_promisc_stream_t));
        if (RT_UNLIKELY(!pPromiscStream))
        {
            LogRel((DEVICE_NAME ":VBoxNetFltSolarisModOpen failed to allocate promiscuous stream data.\n"));
            return ENOMEM;
        }

        pPromiscStream->fPromisc = false;
        pPromiscStream->fRawMode = false;
        pPromiscStream->ModeReqId = 0;
        pPromiscStream->pHead = NULL;
        pPromiscStream->pTail = NULL;
        pPromiscStream->cLoopback = 0;
        pStream = (vboxnetflt_stream_t *)pPromiscStream;
    }
    else
    {
        /*
         * Allocate & initialize per-stream data. Hook it into the (read and write) queue's module specific data.
         */
        pStream = RTMemAlloc(sizeof(vboxnetflt_stream_t));
        if (RT_UNLIKELY(!pStream))
        {
            LogRel((DEVICE_NAME ":VBoxNetFltSolarisModOpen failed to allocate stream data.\n"));
            return ENOMEM;
        }
    }
    pStream->DevMinor = DevMinor;
    pStream->pReadQueue = pQueue;

    /*
     * Pick up the current global VBOXNETFLTINS instance as
     * the one that we will associate this stream with.
     */
    ASMAtomicUoWritePtr((void * volatile *)&pStream->pThis, pThis);
    pStream->Type = g_VBoxNetFltSolarisStreamType;
    switch (pStream->Type)
    {
        case kIp4Stream:        ASMAtomicUoWritePtr((void * volatile *)&pThis->u.s.pvIp4Stream, pStream);        break;
        case kIp6Stream:        ASMAtomicUoWritePtr((void * volatile *)&pThis->u.s.pvIp6Stream, pStream);        break;
        case kArpStream:        ASMAtomicUoWritePtr((void * volatile *)&pThis->u.s.pvArpStream, pStream);        break;
        case kPromiscStream:    ASMAtomicUoWritePtr((void * volatile *)&pThis->u.s.pvPromiscStream, pStream);    break;
        default:    /* Heh. */
        {
            AssertRelease(pStream->Type);
            break;
        }
    }

    pQueue->q_ptr = pStream;
    WR(pQueue)->q_ptr = pStream;

    /*
     * Link it to the list of streams.
     */
    pStream->pNext = *ppPrevStream;
    *ppPrevStream = pStream;

    qprocson(pQueue);

    /*
     * Don't hold the spinlocks across putnext calls as it could
     * (and does mostly) re-enter the put procedure on the same thread.
     */
    if (pStream->Type == kPromiscStream)
    {
        vboxnetflt_promisc_stream_t *pPromiscStream = (vboxnetflt_promisc_stream_t *)pStream;

        /*
         * Bind to SAP 0 (DL_ETHER).
         * Note: We don't support DL_TPR (token passing ring) SAP as that is unnecessary asynchronous
         * work to get DL_INFO_REQ acknowledgements and determine SAP based on the Mac Type etc.
         * Besides TPR doesn't really exist anymore practically as far as I know.
         */
        int rc = vboxNetFltSolarisBindReq(pStream->pReadQueue, 0 /* SAP */);
        if (RT_LIKELY(RT_SUCCESS(rc)))
        {
            /*
             * Request the physical address (we cache the acknowledgement).
             */
            /** @todo take a look at DLPI notifications additionally for these things. */
            rc = vboxNetFltSolarisPhysAddrReq(pStream->pReadQueue);
            if (RT_LIKELY(RT_SUCCESS(rc)))
            {
                /*
                 * Ask for DLPI link notifications, don't bother check for errors here.
                 */
                vboxNetFltSolarisNotifyReq(pStream->pReadQueue);

                /*
                 * Enable raw mode.
                 */
                rc = vboxNetFltSolarisSetRawMode(pPromiscStream);
                if (RT_FAILURE(rc))
                    LogRel((DEVICE_NAME ":vboxNetFltSolarisSetRawMode failed rc=%Rrc.\n", rc));
            }
            else
                LogRel((DEVICE_NAME ":vboxNetFltSolarisSetRawMode failed rc=%Rrc.\n", rc));
        }
        else
            LogRel((DEVICE_NAME ":vboxNetFltSolarisBindReq failed rc=%Rrc.\n", rc));
    }

    NOREF(fOpenMode);
    NOREF(pCred);

    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModOpen returns 0, DevMinor=%d pQueue=%p\n", DevMinor, pStream->pReadQueue));

    return 0;
}


/**
 * Stream module close entry point, undoes the work done on open and closes the stream.
 *
 * @param   pQueue          Pointer to the queue (cannot be NULL).
 * @param   fOpenMode       Open mode (always 0 for streams driver, thus ignored).
 * @param   pCred           Pointer to user credentials.
 *
 * @returns  corresponding solaris error code.
 */
static int VBoxNetFltSolarisModClose(queue_t *pQueue, int fOpenMode, cred_t *pCred)
{
    Assert(pQueue);

    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModClose pQueue=%p fOpenMode=%d\n", pQueue, fOpenMode));

    vboxnetflt_stream_t *pStream = NULL;
    vboxnetflt_stream_t **ppPrevStream = NULL;

    /*
     * Get instance data.
     */
    pStream = (vboxnetflt_stream_t *)pQueue->q_ptr;
    if (RT_UNLIKELY(!pStream))
    {
        LogRel((DEVICE_NAME ":VBoxNetFltSolarisModClose failed to get stream.\n"));
        return ENXIO;
    }

    if (pStream->Type == kPromiscStream)
    {
        flushq(pQueue, FLUSHALL);
        flushq(WR(pQueue), FLUSHALL);
    }

    qprocsoff(pQueue);

    if (pStream->Type == kPromiscStream)
    {
        vboxnetflt_promisc_stream_t *pPromiscStream = (vboxnetflt_promisc_stream_t *)pStream;

        int rc = RTSemFastMutexRequest(pStream->pThis->u.s.hFastMtx);
        AssertRCReturn(rc, rc);

        /*
         * Free-up loopback buffers.
         */
        PVBOXNETFLTPACKETID pCur = pPromiscStream->pHead;
        while (pCur)
        {
            PVBOXNETFLTPACKETID pNext = pCur->pNext;
            RTMemFree(pCur);
            pCur = pNext;
        }
        pPromiscStream->pHead = NULL;
        pPromiscStream->pTail = NULL;
        pPromiscStream->cLoopback = 0;

        RTSemFastMutexRelease(pStream->pThis->u.s.hFastMtx);
    }

    /*
     * Unlink it from the list of streams.
     */
    for (ppPrevStream = &g_VBoxNetFltSolarisStreams; (pStream = *ppPrevStream) != NULL; ppPrevStream = &pStream->pNext)
        if (pStream == (vboxnetflt_stream_t *)pQueue->q_ptr)
            break;
    *ppPrevStream = pStream->pNext;

    /*
     * Delete the stream.
     */
    switch (pStream->Type)
    {
        case kIp4Stream:        ASMAtomicUoWritePtr(pStream->pThis->u.s.pvIp4Stream, NULL);     break;
        case kIp6Stream:        ASMAtomicUoWritePtr(pStream->pThis->u.s.pvIp6Stream, NULL);     break;
        case kArpStream:        ASMAtomicUoWritePtr(pStream->pThis->u.s.pvArpStream, NULL);     break;
        case kPromiscStream:    ASMAtomicUoWritePtr(pStream->pThis->u.s.pvPromiscStream, NULL); break;
        default:    /* Heh. */
        {
            AssertRelease(pStream->Type);
            break;
        }
    }

    vboxNetFltRelease(pStream->pThis, false /* fBusy */);
    RTMemFree(pStream);
    pQueue->q_ptr = NULL;
    WR(pQueue)->q_ptr = NULL;

    NOREF(fOpenMode);
    NOREF(pCred);

    return 0;
}


/**
 * Read side put procedure for processing messages in the read queue.
 * All streams, bound and unbound share this read procedure.
 *
 * @param   pQueue      Pointer to the queue.
 * @param   pMsg        Pointer to the message.
 *
 * @returns corresponding solaris error code.
 */
static int VBoxNetFltSolarisModReadPut(queue_t *pQueue, mblk_t *pMsg)
{
    if (!pMsg)
        return 0;

    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut pQueue=%p pMsg=%p\n", pQueue, pMsg));

    bool fSendUpstream = true;
    vboxnetflt_stream_t *pStream = pQueue->q_ptr;
    PVBOXNETFLTINS pThis = NULL;

    /*
     * In the unlikely case where VirtualBox crashed and this filter
     * is somehow still in the host stream we must try not to panic the host.
     */
    if (   pStream
        && pStream->Type == kPromiscStream)
    {
        pThis = ASMAtomicUoReadPtr((void * volatile *)&pStream->pThis);
        if (RT_LIKELY(pThis))
        {
            /*
             * Retain the instance if we're filtering regardless of we are active or not
             * The reason being even when we are inactive we reference the instance (e.g
             * the promiscuous OFF acknowledgement case).
             */
            RTSPINLOCKTMP Tmp = RTSPINLOCKTMP_INITIALIZER;
            RTSpinlockAcquire(pThis->hSpinlock, &Tmp);
            const bool fActive = ASMAtomicUoReadBool(&pThis->fActive);
            vboxNetFltRetain(pThis, true /* fBusy */);
            RTSpinlockRelease(pThis->hSpinlock, &Tmp);

            vboxnetflt_promisc_stream_t *pPromiscStream = (vboxnetflt_promisc_stream_t *)pStream;

            switch (DB_TYPE(pMsg))
            {
                case M_DATA:
                {
                    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut M_DATA\n"));

                    if (   fActive
                        && pPromiscStream->fRawMode)
                    {
                        vboxNetFltSolarisRecv(pThis, pStream, pQueue, pMsg);
                        pMsg = NULL;
                        fSendUpstream = false;
                    }
                    break;
                }

                case M_PROTO:
                case M_PCPROTO:
                {
                    union DL_primitives *pPrim = (union DL_primitives *)pMsg->b_rptr;
                    t_uscalar_t Prim = pPrim->dl_primitive;

                    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: M_PCPROTO %d\n", Prim));
                    switch (Prim)
                    {
                        case DL_NOTIFY_IND:
                        {
                            if (MBLKL(pMsg) < DL_NOTIFY_IND_SIZE)
                            {
                                LogRel((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: Invalid notification size; expected>=%d got=%d\n",
                                            DL_NOTIFY_IND_SIZE, MBLKL(pMsg)));

                                fSendUpstream = false;
                                break;
                            }

                            dl_notify_ind_t *pNotifyInd = (dl_notify_ind_t *)pMsg->b_rptr;
                            switch (pNotifyInd->dl_notification)
                            {
                                case DL_NOTE_PHYS_ADDR:
                                {
                                    if (pNotifyInd->dl_data != DL_CURR_PHYS_ADDR)
                                        break;

                                    size_t cOffset = pNotifyInd->dl_addr_offset;
                                    size_t cbAddr = pNotifyInd->dl_addr_length;

                                    if (!cOffset || !cbAddr)
                                    {
                                        LogRel((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: DL_NOTE_PHYS_ADDR. Invalid offset/addr.\n"));
                                        fSendUpstream = false;
                                        break;
                                    }

                                    bcopy(pMsg->b_rptr + cOffset, &pThis->u.s.Mac, sizeof(pThis->u.s.Mac));
                                    fSendUpstream = false;
                                    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: DL_NOTE_PHYS_ADDR. New Mac=%.*Rhxs\n",
                                        sizeof(pThis->u.s.Mac), &pThis->u.s.Mac));
                                    break;
                                }

                                case DL_NOTE_LINK_UP:
                                {
                                    const bool fDisconnected = ASMAtomicUoReadBool(&pThis->fActive);
                                    if (fDisconnected)
                                    {
                                        ASMAtomicWriteBool(&pThis->fDisconnectedFromHost, false);
                                        LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: DL_NOTE_LINK_UP.\n"));
                                    }
                                    fSendUpstream = false;
                                    break;
                                }

                                case DL_NOTE_LINK_DOWN:
                                {
                                    const bool fDisconnected = ASMAtomicUoReadBool(&pThis->fActive);
                                    if (!fDisconnected)
                                    {
                                        ASMAtomicWriteBool(&pThis->fDisconnectedFromHost, true);
                                        LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: DL_NOTE_LINK_DOWN.\n"));
                                    }
                                    fSendUpstream = false;
                                    break;
                                }
                            }
                            break;
                        }

                        case DL_BIND_ACK:
                        {
                            /*
                             * Swallow our bind request acknowledgement.
                             */
                            LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: DL_BIND_ACK. Bound to requested SAP!\n"));
                            fSendUpstream = false;
                            break;
                        }

                        case DL_PHYS_ADDR_ACK:
                        {
                            /*
                             * Swallow our physical address request acknowledgement.
                             */
                            vboxNetFltSolarisCachePhysAddr(pThis, pMsg);
                            fSendUpstream = false;
                            break;
                        }

                        case DL_OK_ACK:
                        {
                            /*
                             * Swallow our fake promiscous request acknowledgement.
                             */
                            dl_ok_ack_t *pOkAck = (dl_ok_ack_t *)pMsg->b_rptr;
                            if (pOkAck->dl_correct_primitive == DL_PROMISCON_REQ)
                            {
                                LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: M_PCPROTO: DL_OK_ACK: fPromisc is ON.\n"));
                                pPromiscStream->fPromisc = true;
                            }
                            else if (pOkAck->dl_correct_primitive == DL_PROMISCOFF_REQ)
                            {
                                LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: M_PCPROTO: DL_OK_ACK: fPromisc is OFF.\n"));
                                pPromiscStream->fPromisc = false;
                            }

                            fSendUpstream = false;
                            break;
                        }
                    }
                    break;
                }

                case M_IOCACK:
                {
                    /*
                     * Swallow our fake raw/fast path mode request acknowledgement.
                     */
                    struct iocblk *pIOC = (struct iocblk *)pMsg->b_rptr;
                    if (pIOC->ioc_id == pPromiscStream->ModeReqId)
                    {
                        pPromiscStream->fRawMode = true;
                        LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: Mode acknowledgement. RawMode is %s\n",
                                pPromiscStream->fRawMode ? "ON" : "OFF"));

                        fSendUpstream = false;
                    }
                    break;
                }

                case M_FLUSH:
                {
                    /*
                     * We must support flushing queues.
                     */
                    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: M_FLUSH\n"));
                    if (*pMsg->b_rptr & FLUSHR)
                        flushq(pQueue, FLUSHALL);
                    break;
                }
            }

            vboxNetFltRelease(pThis, true /* fBusy */);
        }
        else
            LogRel((DEVICE_NAME ":VBoxNetFltSolarisModReadPut: Could not find VirtualBox instance!!\n"));
    }

    if (fSendUpstream)
    {
        /*
         * Don't queue up things here, can cause bad things to happen when the system
         * is under heavy loads and we need to jam across high priority messages which
         * if it's not done properly will end up in an infinite loop.
         */
        putnext(pQueue, pMsg);
    }
    else if (pMsg)
    {
        /*
         * We need to free up the message if we don't pass it through.
         */
        freemsg(pMsg);
    }

    return 0;
}


/**
 * Write side put procedure for processing messages in the write queue.
 * All streams, bound and unbound share this write procedure.
 *
 * @param   pQueue      Pointer to the queue.
 * @param   pMsg        Pointer to the message.
 *
 * @returns corresponding solaris error code.
 */
static int VBoxNetFltSolarisModWritePut(queue_t *pQueue, mblk_t *pMsg)
{
    LogFlow((DEVICE_NAME ":VBoxNetFltSolarisModWritePut pQueue=%p pMsg=%p\n", pQueue, pMsg));

    putnext(pQueue, pMsg);
    return 0;
}


/**
 * Put the stream in raw mode.
 *
 * @returns VBox status code.
 * @param   pQueue      Pointer to the queue.
 */
static int vboxNetFltSolarisSetRawMode(vboxnetflt_promisc_stream_t *pPromiscStream)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisSetRawMode pPromiscStream=%p\n", pPromiscStream));

    mblk_t *pRawMsg = NULL;
    pRawMsg = mkiocb(DLIOCRAW);
    if (RT_UNLIKELY(!pRawMsg))
        return VERR_NO_MEMORY;

    queue_t *pQueue = pPromiscStream->Stream.pReadQueue;
    if (!pQueue)
        return VERR_INVALID_POINTER;

    struct iocblk *pIOC = (struct iocblk *)pRawMsg->b_rptr;
    pPromiscStream->ModeReqId = pIOC->ioc_id;
    pIOC->ioc_count = 0;

    qreply(pQueue, pRawMsg);
    return VINF_SUCCESS;
}


#if 0
/**
 * Put the stream back in fast path mode.
 *
 * @returns VBox status code.
 * @param   pQueue      Pointer to the queue.
 */
static int vboxNetFltSolarisSetFastMode(queue_t *pQueue)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisSetFastMode pQueue=%p\n", pQueue));

    mblk_t *pFastMsg = mkiocb(DL_IOC_HDR_INFO);
    if (RT_UNLIKELY(!pFastMsg))
        return VERR_NO_MEMORY;

    vboxnetflt_stream_t *pStream = pQueue->q_ptr;
    struct iocblk *pIOC = (struct iocblk *)pFastMsg->b_rptr;
    pStream->ModeReqId = pIOC->ioc_id;

    size_t cbReq = sizeof(dl_unitdata_req_t) + sizeof(vboxnetflt_dladdr_t);
    mblk_t *pDataReqMsg = allocb(cbReq, BPRI_MED);
    if (RT_UNLIKELY(!pDataReqMsg))
        return VERR_NO_MEMORY;

    DB_TYPE(pDataReqMsg) = M_PROTO;
    dl_unitdata_req_t *pDataReq = (dl_unitdata_req_t *)pDataReqMsg->b_rptr;
    pDataReq->dl_primitive = DL_UNITDATA_REQ;
    pDataReq->dl_dest_addr_length = sizeof(vboxnetflt_dladdr_t);
    pDataReq->dl_dest_addr_offset = sizeof(dl_unitdata_req_t);
    pDataReq->dl_priority.dl_min = 0;
    pDataReq->dl_priority.dl_max = 0;

    bzero(pDataReqMsg->b_rptr + sizeof(dl_unitdata_req_t), sizeof(vboxnetflt_dladdr_t));
    pDataReqMsg->b_wptr = pDataReqMsg->b_rptr + cbReq;

    /*
     * Link the data format request message into the header ioctl message.
     */
    pFastMsg->b_cont = pDataReqMsg;
    pIOC->ioc_count = msgdsize(pDataReqMsg);

    qreply(pQueue, pFastMsg);
    return VINF_SUCCESS;
}
#endif


/**
 * Send fake promiscous mode requests downstream.
 *
 * @param   pQueue          Pointer to the queue.
 * @param   fPromisc        Whether to enable promiscous mode or not.
 * @param   PromiscLevel    Promiscous level; DL_PROMISC_PHYS/SAP/MULTI.
 *
 * @returns VBox error code.
 */
static int vboxNetFltSolarisPromiscReq(queue_t *pQueue, bool fPromisc)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisPromiscReq pQueue=%p fPromisc=%d\n", pQueue, fPromisc));

    t_uscalar_t Cmd;
    size_t cbReq = 0;
    if (fPromisc)
    {
        Cmd = DL_PROMISCON_REQ;
        cbReq = DL_PROMISCON_REQ_SIZE;
    }
    else
    {
        Cmd = DL_PROMISCOFF_REQ;
        cbReq = DL_PROMISCOFF_REQ_SIZE;
    }

    mblk_t *pPromiscPhysMsg = mexchange(NULL, NULL, cbReq, M_PROTO, Cmd);
    if (RT_UNLIKELY(!pPromiscPhysMsg))
        return VERR_NO_MEMORY;

    mblk_t *pPromiscSapMsg = mexchange(NULL, NULL, cbReq, M_PROTO, Cmd);
    if (RT_UNLIKELY(!pPromiscSapMsg))
    {
        freemsg(pPromiscPhysMsg);
        return VERR_NO_MEMORY;
    }

    if (fPromisc)
    {
        ((dl_promiscon_req_t *)pPromiscPhysMsg->b_rptr)->dl_level = DL_PROMISC_PHYS;
        ((dl_promiscon_req_t *)pPromiscSapMsg->b_rptr)->dl_level = DL_PROMISC_SAP;
    }
    else
    {
        ((dl_promiscoff_req_t *)pPromiscPhysMsg->b_rptr)->dl_level = DL_PROMISC_PHYS;
        ((dl_promiscoff_req_t *)pPromiscSapMsg->b_rptr)->dl_level = DL_PROMISC_SAP;
    }

    qreply(pQueue, pPromiscPhysMsg);
    qreply(pQueue, pPromiscSapMsg);

    return VINF_SUCCESS;
}


/**
 * Send a fake physical address request downstream.
 *
 * @returns VBox status code.
 * @param   pQueue      Pointer to the queue.
 * @param   pMsg        Pointer to the request message.
 */
static int vboxNetFltSolarisPhysAddrReq(queue_t *pQueue)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisPhysAddrReq pQueue=%p\n", pQueue));

    t_uscalar_t Cmd = DL_PHYS_ADDR_REQ;
    size_t cbReq = DL_PHYS_ADDR_REQ_SIZE;
    mblk_t *pPhysAddrMsg = mexchange(NULL, NULL, cbReq, M_PROTO, Cmd);
    if (RT_UNLIKELY(!pPhysAddrMsg))
        return VERR_NO_MEMORY;

    dl_phys_addr_req_t *pPhysAddrReq = (dl_phys_addr_req_t *)pPhysAddrMsg->b_rptr;
    pPhysAddrReq->dl_addr_type = DL_CURR_PHYS_ADDR;

    qreply(pQueue, pPhysAddrMsg);
    return VINF_SUCCESS;
}


/**
 * Cache the MAC address into the VirtualBox instance given a physical
 * address acknowledgement message.
 *
 * @param   pThis       The instance.
 * @param   pMsg        Pointer to the physical address acknowledgement message.
 */
static void vboxNetFltSolarisCachePhysAddr(PVBOXNETFLTINS pThis, mblk_t *pMsg)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisCachePhysAddr pThis=%p pMsg=%p\n", pThis, pMsg));

    AssertCompile(sizeof(RTMAC) == ETHERADDRL);
    dl_phys_addr_ack_t *pPhysAddrAck = (dl_phys_addr_ack_t *)pMsg->b_rptr;
    if (pPhysAddrAck->dl_addr_length == sizeof(pThis->u.s.Mac))
    {
        bcopy(pMsg->b_rptr + pPhysAddrAck->dl_addr_offset, &pThis->u.s.Mac, sizeof(pThis->u.s.Mac));

        LogFlow((DEVICE_NAME ":vboxNetFltSolarisCachePhysAddr: DL_PHYS_ADDR_ACK: Mac=%.*Rhxs\n", sizeof(pThis->u.s.Mac),
                    &pThis->u.s.Mac));
    }
    else
    {
        LogRel((DEVICE_NAME ":vboxNetFltSolarisCachePhysAddr: Invalid address size. expected=%d got=%d\n", ETHERADDRL,
                pPhysAddrAck->dl_addr_length));
    }
}


/**
 * Prepare DLPI bind request to a SAP.
 *
 * @returns VBox status code.
 * @param   pQueue      Pointer to the queue.
 * @param   SAP         The SAP to bind the stream to.
 */
static int vboxNetFltSolarisBindReq(queue_t *pQueue, int SAP)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisBindReq SAP=%d\n", SAP));

    mblk_t *pBindMsg = mexchange(NULL, NULL, DL_BIND_REQ_SIZE, M_PROTO, DL_BIND_REQ);
    if (RT_UNLIKELY(!pBindMsg))
        return VERR_NO_MEMORY;

    dl_bind_req_t *pBindReq = (dl_bind_req_t *)pBindMsg->b_rptr;
    pBindReq->dl_sap = SAP;
    pBindReq->dl_max_conind = 0;
    pBindReq->dl_conn_mgmt = 0;
    pBindReq->dl_xidtest_flg = 0;
    pBindReq->dl_service_mode = DL_CLDLS;

    qreply(pQueue, pBindMsg);
    return VINF_SUCCESS;
}


/**
 * Prepare DLPI notifications request.
 *
 * @returns VBox status code.
 * @param   pQueue          Pointer to the queue.
 */
static int vboxNetFltSolarisNotifyReq(queue_t *pQueue)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisNotifyReq\n"));

    mblk_t *pNotifyMsg = mexchange(NULL, NULL, DL_NOTIFY_REQ_SIZE, M_PROTO, DL_NOTIFY_REQ);
    if (RT_UNLIKELY(!pNotifyMsg))
        return VERR_NO_MEMORY;

    dl_notify_req_t *pNotifyReq = (dl_notify_req_t *)pNotifyMsg->b_rptr;
    pNotifyReq->dl_notifications = DL_NOTE_LINK_UP | DL_NOTE_LINK_DOWN | DL_NOTE_PHYS_ADDR;

    qreply(pQueue, pNotifyMsg);
    return VINF_SUCCESS;
}


/**
 * Opens the required device and returns the vnode_t associated with it.
 * We require this for the funny attach/detach routine.
 *
 * @returns VBox status code.
 * @param   pszDev          The device path.
 * @param   ppVNode         Where to store the vnode_t pointer associated with the opened device.
 * @param   ppVNodeHeld     Where to store the vnode_t required during closing of the device.
 * @param   ppUser          Open handle required while closing the device.
 */
static int vboxNetFltSolarisOpenDev(char *pszDev, vnode_t **ppVNode, vnode_t **ppVNodeHeld, TIUSER **ppUser)
{
    int rc;
    vnode_t *pVNodeHeld = NULL;
    rc = lookupname(pszDev, UIO_SYSSPACE, FOLLOW, NULLVPP, &pVNodeHeld);
    if (!rc)
    {
        TIUSER *pUser;
        rc = t_kopen((file_t *)NULL, pVNodeHeld->v_rdev, FREAD | FWRITE, &pUser, kcred);
        if (!rc)
        {
            *ppVNode = pUser->fp->f_vnode;
            *ppVNodeHeld = pVNodeHeld;
            *ppUser = pUser;
            return VINF_SUCCESS;
        }
        VN_RELE(pVNodeHeld);
    }
    return VERR_PATH_NOT_FOUND;
}


/**
 * Close the device opened using vboxNetFltSolarisOpenDev.
 *
 * @param   pVNodeHeld      Pointer to the held vnode of the device.
 * @param   pUser           Pointer to the file handle.
 */
static void vboxNetFltSolarisCloseDev(vnode_t *pVNodeHeld, TIUSER *pUser)
{
    t_kclose(pUser, 0);
    VN_RELE(pVNodeHeld);
}


/**
 * Get the logical interface flags from the stream.
 *
 * @returns VBox status code.
 * @param   hDevice        Layered device handle.
 * @param   pInterface     Pointer to the interface.
 */
static int vboxNetFltSolarisGetIfFlags(ldi_handle_t hDevice, struct lifreq *pInterface)
{
    struct strioctl IOCReq;
    int rc;
    int ret;
    IOCReq.ic_cmd = SIOCGLIFFLAGS;
    IOCReq.ic_timout = 40;
    IOCReq.ic_len = sizeof(struct lifreq);
    IOCReq.ic_dp = (caddr_t)pInterface;
    rc = ldi_ioctl(hDevice, I_STR, (intptr_t)&IOCReq, FKIOCTL, kcred, &ret);
    if (!rc)
        return VINF_SUCCESS;

    return RTErrConvertFromErrno(rc);
}


/**
 * Sets the multiplexor ID from the interface.
 *
 * @returns VBox status code.
 * @param   pVNode      Pointer to the device vnode.
 * @param   pInterface  Pointer to the interface.
 */
static int vboxNetFltSolarisSetMuxId(vnode_t *pVNode, struct lifreq *pInterface)
{
    struct strioctl IOCReq;
    int rc;
    int ret;
    IOCReq.ic_cmd = SIOCSLIFMUXID;
    IOCReq.ic_timout = 40;
    IOCReq.ic_len = sizeof(struct lifreq);
    IOCReq.ic_dp = (caddr_t)pInterface;

    rc = strioctl(pVNode, I_STR, (intptr_t)&IOCReq, 0, K_TO_K, kcred, &ret);
    if (!rc)
        return VINF_SUCCESS;

    return RTErrConvertFromErrno(rc);
}


/**
 * Get the multiplexor file descriptor of the lower stream.
 *
 * @returns VBox status code.
 * @param   MuxId   The multiplexor ID.
 * @param   pFd     Where to store the lower stream file descriptor.
 */
static int vboxNetFltSolarisMuxIdToFd(vnode_t *pVNode, int MuxId, int *pFd)
{
    int ret;
    int rc = strioctl(pVNode, _I_MUXID2FD, (intptr_t)MuxId, 0, K_TO_K, kcred, &ret);
    if (!rc)
    {
        *pFd = ret;
        return VINF_SUCCESS;
    }

    return RTErrConvertFromErrno(rc);
}


/**
 * Relinks the lower and the upper IPv4 stream.
 *
 * @returns VBox status code.
 * @param   pVNode      Pointer to the device vnode.
 * @param   pInterface  Pointer to the interface.
 * @param   IpMuxFd     The IP multiplexor ID.
 * @param   ArpMuxFd    The ARP multiplexor ID.
 */
static int vboxNetFltSolarisRelinkIp4(vnode_t *pVNode, struct lifreq *pInterface, int IpMuxFd, int ArpMuxFd)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisRelinkIp4: pVNode=%p pInterface=%p IpMuxFd=%d ArpMuxFd=%d\n", pVNode,
            pInterface, IpMuxFd, ArpMuxFd));

    int NewIpMuxId;
    int NewArpMuxId;
    int rc = strioctl(pVNode, I_PLINK, (intptr_t)IpMuxFd, 0, K_TO_K, kcred, &NewIpMuxId);
    int rc2 = strioctl(pVNode, I_PLINK, (intptr_t)ArpMuxFd, 0, K_TO_K, kcred, &NewArpMuxId);
    if (   !rc
        && !rc2)
    {
        pInterface->lifr_ip_muxid = NewIpMuxId;
        pInterface->lifr_arp_muxid = NewArpMuxId;
        rc = vboxNetFltSolarisSetMuxId(pVNode, pInterface);
        if (RT_SUCCESS(rc))
            return VINF_SUCCESS;

        LogRel((DEVICE_NAME ":vboxNetFltSolarisRelinkIp4: failed to set new Mux Id.\n"));
    }
    else
        LogRel((DEVICE_NAME ":vboxNetFltSolarisRelinkIp4: failed to link.\n"));

    return VERR_GENERAL_FAILURE;
}


/**
 * Relinks the lower and the upper IPv6 stream.
 *
 * @returns VBox status code.
 * @param   pVNode      Pointer to the device vnode.
 * @param   pInterface  Pointer to the interface.
 * @param   Ip6MuxFd    The IPv6 multiplexor ID.
 */
static int vboxNetFltSolarisRelinkIp6(vnode_t *pVNode, struct lifreq *pInterface, int Ip6MuxFd)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisRelinkIp6: pVNode=%p pInterface=%p Ip6MuxFd=%d\n", pVNode, pInterface, Ip6MuxFd));

    int NewIp6MuxId;
    int rc = strioctl(pVNode, I_PLINK, (intptr_t)Ip6MuxFd, 0, K_TO_K, kcred, &NewIp6MuxId);
    if (!rc)
    {
        pInterface->lifr_ip_muxid = NewIp6MuxId;
        rc = vboxNetFltSolarisSetMuxId(pVNode, pInterface);
        if (RT_SUCCESS(rc))
            return VINF_SUCCESS;

        LogRel((DEVICE_NAME ":vboxNetFltSolarisRelinkIp6: failed to set new Mux Id.\n"));
    }
    else
        LogRel((DEVICE_NAME ":vboxNetFltSolarisRelinkIp6: failed to link.\n"));

    return VERR_GENERAL_FAILURE;
}


/**
 * Dynamically find the position on the host stack where to attach/detach ourselves.
 *
 * @returns VBox status code.
 * @param   pVNode      Pointer to the lower stream vnode.
 * @param   pModPos     Where to store the module position.
 */
static int vboxNetFltSolarisDetermineModPos(bool fAttach, vnode_t *pVNode, int *pModPos)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisDetermineModPos: fAttach=%d pVNode=%p pModPos=%p\n", fAttach, pVNode, pModPos));

    int cMod;
    int rc = strioctl(pVNode, I_LIST, (intptr_t)NULL, 0, K_TO_K, kcred, &cMod);
    if (!rc)
    {
        if (cMod < 1)
        {
            LogRel((DEVICE_NAME ":vboxNetFltSolarisDetermineModPos: too few modules on host interface. cMod=%d\n"));
            return VERR_OUT_OF_RANGE;
        }

        /*
         * While attaching we make sure we are at the bottom most of the stack, excepting
         * the host driver.
         */
        LogFlow((DEVICE_NAME ":vboxNetFltSolarisDetermineModPos: cMod=%d\n", cMod));
        if (fAttach)
        {
            *pModPos = cMod - 1;
            return VINF_SUCCESS;
        }

        /*
         * Detaching is a bit more complicated; since user could have altered the stack positions
         * we take the safe approach by finding our position.
         */
        struct str_list StrList;
        StrList.sl_nmods = cMod;
        StrList.sl_modlist = RTMemAllocZ(cMod * sizeof(struct str_list));
        if (RT_UNLIKELY(!StrList.sl_modlist))
        {
            LogFlow((DEVICE_NAME ":vboxNetFltSolarisDetermineModPos: failed to alloc memory for StrList.\n"));
            return VERR_NO_MEMORY;
        }

        /*
         * Get the list of all modules on the stack.
         */
        int ret;
        rc = strioctl(pVNode, I_LIST, (intptr_t)&StrList, 0, K_TO_K, kcred, &ret);
        if (!rc)
        {
            /*
             * Find our filter.
             */
            for (int i = 0; i < StrList.sl_nmods; i++)
            {
                if (!strcmp(DEVICE_NAME, StrList.sl_modlist[i].l_name))
                {
                    LogFlow((DEVICE_NAME ":vboxNetFltSolarisDetermineModPos: Success! Found %s at %d.\n", DEVICE_NAME, i));
                    *pModPos = i;
                    RTMemFree(StrList.sl_modlist);
                    return VINF_SUCCESS;
                }
            }

            LogRel((DEVICE_NAME ":vboxNetFltSolarisDetermineModPos: failed to find %s in the host stack.\n"));
        }
        else
            LogRel((DEVICE_NAME ":vboxNetFltSolarisDetermineModPos: failed to get module information. rc=%d\n"));

        RTMemFree(StrList.sl_modlist);
    }
    else
        LogRel((DEVICE_NAME ":vboxNetFltSolarisDetermineModPos: failed to get list of modules on host interface. rc=%d\n", rc));
    return VERR_GENERAL_FAILURE;
}


/**
 * Opens up dedicated stream on top of the interface.
 * As a side-effect, the stream gets opened during
 * the I_PUSH phase.
 *
 * @param   pThis       The instance.
 */
static int vboxNetFltSolarisOpenStream(PVBOXNETFLTINS pThis)
{
    ldi_ident_t DevId;
    DevId = ldi_ident_from_anon();
    int ret;

    /** @todo support DLPI style 2.*/
    /*
     * Try style-1 open first.
     */
    char szDev[128];
    RTStrPrintf(szDev, sizeof(szDev), "/dev/net/%s", pThis->szName);
    int rc = ldi_open_by_name(szDev, FREAD | FWRITE, kcred, &pThis->u.s.hIface, DevId);
    if (   rc
        && rc == ENODEV)    /* ENODEV is returned when resolvepath fails, not ENOENT */
    {
        /*
         * Fallback to non-ClearView style-1 open.
         */
        RTStrPrintf(szDev, sizeof(szDev), "/dev/%s", pThis->szName);
        rc = ldi_open_by_name(szDev, FREAD | FWRITE, kcred, &pThis->u.s.hIface, DevId);
    }

    ldi_ident_release(DevId);
    if (rc)
    {
        LogRel((DEVICE_NAME ":vboxNetFltSolarisOpenStream Failed to open '%s' rc=%d\n", szDev, rc));
        return VERR_INTNET_FLT_IF_FAILED;
    }

    rc = ldi_ioctl(pThis->u.s.hIface, I_FIND, (intptr_t)DEVICE_NAME, FKIOCTL, kcred, &ret);
    if (!rc)
    {
        if (!ret)
        {
            g_VBoxNetFltSolarisInstance = pThis;
            g_VBoxNetFltSolarisStreamType = kPromiscStream;

            rc = ldi_ioctl(pThis->u.s.hIface, I_PUSH, (intptr_t)DEVICE_NAME, FKIOCTL, kcred, &ret);

            g_VBoxNetFltSolarisInstance = NULL;
            g_VBoxNetFltSolarisStreamType = kUndefined;

            if (!rc)
                return VINF_SUCCESS;

            LogRel((DEVICE_NAME ":vboxNetFltSolarisOpenStream Failed to push filter onto host interface '%s'\n", pThis->szName));
        }
        else
            return VINF_SUCCESS;
    }
    else
        LogRel((DEVICE_NAME ":vboxNetFltSolarisOpenStream Failed to search for filter in interface '%s'.\n", pThis->szName));

    return VERR_INTNET_FLT_IF_FAILED;
}


/**
 * Closes the interface, thereby closing the dedicated stream.
 *
 * @param   pThis       The instance.
 */
static void vboxNetFltSolarisCloseStream(PVBOXNETFLTINS pThis)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisCloseStream pThis=%p\n"));

    vboxNetFltRetain(pThis, false /* fBusy */);

    ldi_close(pThis->u.s.hIface, FREAD | FWRITE, kcred);
}


/**
 * Dynamically attach under IPv4 and ARP streams on the host stack.
 *
 * @returns VBox status code.
 * @param   pThis       The instance.
 * @param   fAttach     Is this an attach or detach.
 */
static int vboxNetFltSolarisAttachIp4(PVBOXNETFLTINS pThis, bool fAttach)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisAttachIp4 pThis=%p fAttach=%d\n", pThis, fAttach));

    /*
     * Statuatory Warning: Hackish code ahead.
     */
    char *pszModName = DEVICE_NAME;

    struct lifreq Ip4Interface;
    bzero(&Ip4Interface, sizeof(Ip4Interface));
    Ip4Interface.lifr_addr.ss_family = AF_INET;
    strncpy(Ip4Interface.lifr_name, pThis->szName, sizeof(Ip4Interface.lifr_name));

    struct strmodconf StrMod;
    StrMod.mod_name = pszModName;
    StrMod.pos = -1;        /* this is filled in later. */

    struct strmodconf ArpStrMod;
    bcopy(&StrMod, &ArpStrMod, sizeof(StrMod));

    int rc;
    int rc2;
    int ret;
    ldi_ident_t DeviceIdent = ldi_ident_from_anon();
    ldi_handle_t Ip4DevHandle;
    ldi_handle_t ArpDevHandle;

    /*
     * Open the IP and ARP streams as layered devices.
     */
    rc = ldi_open_by_name(IP_DEV_NAME, FREAD | FWRITE, kcred, &Ip4DevHandle, DeviceIdent);
    if (rc)
    {
        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to open the IP stream on '%s'.\n", pThis->szName));
        ldi_ident_release(DeviceIdent);
        return VERR_INTNET_FLT_IF_FAILED;
    }

    rc = ldi_open_by_name("/dev/arp", FREAD | FWRITE, kcred, &ArpDevHandle, DeviceIdent);
    if (rc)
    {
        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to open the ARP stream on '%s'.\n", pThis->szName));
        ldi_ident_release(DeviceIdent);
        ldi_close(Ip4DevHandle, FREAD | FWRITE, kcred);
        return VERR_INTNET_FLT_IF_FAILED;
    }

    ldi_ident_release(DeviceIdent);

    /*
     * Obtain the interface flags from IPv4.
     */
    rc = vboxNetFltSolarisGetIfFlags(Ip4DevHandle, &Ip4Interface);
    if (RT_SUCCESS(rc))
    {
        /*
         * Open the UDP stream. We sort of cheat here and obtain the vnode so that we can perform
         * things that are not possible from the layered interface.
         */
        vnode_t *pUdp4VNode = NULL;
        vnode_t *pUdp4VNodeHeld = NULL;
        TIUSER *pUdp4User = NULL;
        rc = vboxNetFltSolarisOpenDev(UDP_DEV_NAME, &pUdp4VNode, &pUdp4VNodeHeld, &pUdp4User);
        if (RT_SUCCESS(rc))
        {
            /*
             * Get the multiplexor IDs.
             */
            rc = ldi_ioctl(Ip4DevHandle, SIOCGLIFMUXID, (intptr_t)&Ip4Interface, FKIOCTL, kcred, &ret);
            if (!rc)
            {
                /*
                 * Get the multiplex file descriptor to the lower streams. Generally this is lost
                 * once a module is I_PLINK, we need to reobtain it for inserting/removing ourselves from the stack.
                 */
                int Ip4MuxFd;
                int ArpMuxFd;
                rc = vboxNetFltSolarisMuxIdToFd(pUdp4VNode, Ip4Interface.lifr_ip_muxid, &Ip4MuxFd);
                rc2 = vboxNetFltSolarisMuxIdToFd(pUdp4VNode, Ip4Interface.lifr_arp_muxid, &ArpMuxFd);
                if (   RT_SUCCESS(rc)
                    && RT_SUCCESS(rc2))
                {
                    /*
                     * We need to I_PUNLINK on these multiplexor IDs before we can start
                     * operating on the lower stream as insertions are direct operations on the lower stream.
                     */
                    int ret;
                    rc = strioctl(pUdp4VNode, I_PUNLINK, (intptr_t)Ip4Interface.lifr_ip_muxid, 0, K_TO_K, kcred, &ret);
                    rc2 = strioctl(pUdp4VNode, I_PUNLINK, (intptr_t)Ip4Interface.lifr_arp_muxid, 0, K_TO_K, kcred, &ret);
                    if (   !rc
                        && !rc2)
                    {
                        /*
                         * Obtain the vnode from the useless userland file descriptor.
                         */
                        file_t *pIpFile = getf(Ip4MuxFd);
                        file_t *pArpFile = getf(ArpMuxFd);
                        if (   pIpFile
                            && pArpFile
                            && pArpFile->f_vnode
                            && pIpFile->f_vnode)
                        {
                            vnode_t *pIp4VNode = pIpFile->f_vnode;
                            vnode_t *pArpVNode = pArpFile->f_vnode;

                            /*
                             * Find the position on the host stack for attaching/detaching ourselves.
                             */
                            rc = vboxNetFltSolarisDetermineModPos(fAttach, pIp4VNode, &StrMod.pos);
                            rc2 = vboxNetFltSolarisDetermineModPos(fAttach, pArpVNode, &ArpStrMod.pos);
                            if (   RT_SUCCESS(rc)
                                && RT_SUCCESS(rc2))
                            {
                                /*
                                 * Set global data which will be grabbed by ModOpen.
                                 * There is a known (though very unlikely) race here because
                                 * of the inability to pass user data while inserting.
                                 */
                                g_VBoxNetFltSolarisInstance = pThis;
                                g_VBoxNetFltSolarisStreamType = kIp4Stream;

                                /*
                                 * Inject/Eject from the host IP stack.
                                 */
                                if (!fAttach)
                                    vboxNetFltRetain(pThis, false /* fBusy */);
                                rc = strioctl(pIp4VNode, fAttach ? _I_INSERT : _I_REMOVE, (intptr_t)&StrMod, 0, K_TO_K,
                                            kcred, &ret);
                                if (!rc)
                                {
                                    if (!fAttach)
                                        vboxNetFltRetain(pThis, false /* fBusy */);

                                    /*
                                     * Inject/Eject from the host ARP stack.
                                     */
                                    g_VBoxNetFltSolarisStreamType = kArpStream;
                                    rc = strioctl(pArpVNode, fAttach ? _I_INSERT : _I_REMOVE, (intptr_t)&ArpStrMod, 0, K_TO_K,
                                                kcred, &ret);
                                    if (!rc)
                                    {
                                        g_VBoxNetFltSolarisInstance = NULL;
                                        g_VBoxNetFltSolarisStreamType = kUndefined;

                                        /*
                                         * Our job's not yet over; we need to relink the upper and lower streams
                                         * otherwise we've pretty much screwed up the host interface.
                                         */
                                        rc = vboxNetFltSolarisRelinkIp4(pUdp4VNode, &Ip4Interface, Ip4MuxFd, ArpMuxFd);
                                        if (RT_SUCCESS(rc))
                                        {
                                            /*
                                             * Close the devices ONLY during the return from function case; otherwise
                                             * we end up close twice which is an instant kernel panic.
                                             */
                                            vboxNetFltSolarisCloseDev(pUdp4VNodeHeld, pUdp4User);
                                            ldi_close(ArpDevHandle, FREAD | FWRITE, kcred);
                                            ldi_close(Ip4DevHandle, FREAD | FWRITE, kcred);

                                            LogFlow((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: Success! %s %s@(IPv4:%d Arp:%d) "
                                                    "%s interface %s\n", fAttach ? "Injected" : "Ejected", StrMod.mod_name,
                                                    StrMod.pos, ArpStrMod.pos, fAttach ? "to" : "from", pThis->szName));
                                            return VINF_SUCCESS;
                                        }
                                        else
                                        {
                                            LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: Relinking failed. Mode=%s rc=%d.\n",
                                                    fAttach ? "inject" : "eject", rc));
                                        }

                                        /*
                                         * Try failing gracefully during attach.
                                         */
                                        if (fAttach)
                                            strioctl(pIp4VNode, _I_REMOVE, (intptr_t)&StrMod, 0, K_TO_K, kcred, &ret);
                                    }
                                    else
                                    {
                                        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to %s the ARP stack. rc=%d\n",
                                                fAttach ? "inject into" : "eject from", rc));
                                        if (!fAttach)
                                            vboxNetFltRelease(pThis, false /* fBusy */);
                                    }

                                    if (fAttach)
                                        strioctl(pIp4VNode, _I_REMOVE, (intptr_t)&StrMod, 0, K_TO_K, kcred, &ret);

                                    vboxNetFltSolarisRelinkIp4(pUdp4VNode, &Ip4Interface, Ip4MuxFd, ArpMuxFd);
                                }
                                else
                                {
                                    LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to %s the IP stack. rc=%d\n",
                                            fAttach ? "inject into" : "eject from", rc));
                                    if (!fAttach)
                                        vboxNetFltRelease(pThis, false /* fBusy */);
                                }
                            }
                            else
                                LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to find position. rc=%d rc2=%d\n", rc, rc2));
                        }
                        else
                            LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to get vnode from MuxFd.\n"));
                    }
                    else
                        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to unlink upper stream rc=%d rc2=%d.\n", rc, rc2));
                }
                else
                    LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to get MuxFd from MuxId. rc=%d rc2=%d\n"));
            }
            else
                LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to get Mux Ids. rc=%d\n", rc));
            vboxNetFltSolarisCloseDev(pUdp4VNodeHeld, pUdp4User);
        }
        else
            LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: failed to open UDP. rc=%d\n", rc));
    }
    else
    {
        /*
         * This would happen for interfaces that are not plumbed.
         */
        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp4: Warning: seems '%s' is unplumbed.\n", pThis->szName));
        rc = VINF_SUCCESS;
    }

    ldi_close(ArpDevHandle, FREAD | FWRITE, kcred);
    ldi_close(Ip4DevHandle, FREAD | FWRITE, kcred);

    if (RT_SUCCESS(rc))
        return rc;

    return VERR_INTNET_FLT_IF_FAILED;
}


/**
 * Dynamically attach under IPv6 on the host stack.
 *
 * @returns VBox status code.
 * @param   pThis       The instance.
 * @param   fAttach     Is this an attach or detach.
 */
static int vboxNetFltSolarisAttachIp6(PVBOXNETFLTINS pThis, bool fAttach)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisAttachIp6 pThis=%p fAttach=%d\n", pThis, fAttach));

    /*
     * Statuatory Warning: Hackish code ahead.
     */
    char *pszModName = DEVICE_NAME;

    struct lifreq Ip6Interface;
    bzero(&Ip6Interface, sizeof(Ip6Interface));
    Ip6Interface.lifr_addr.ss_family = AF_INET6;
    strncpy(Ip6Interface.lifr_name, pThis->szName, sizeof(Ip6Interface.lifr_name));

    struct strmodconf StrMod;
    StrMod.mod_name = pszModName;
    StrMod.pos = -1;        /* this is filled in later. */

    int rc;
    int rc2;
    int ret;
    ldi_ident_t DeviceIdent = ldi_ident_from_anon();
    ldi_handle_t Ip6DevHandle;
    ldi_handle_t Udp6DevHandle;

    /*
     * Open the IPv6 stream as a layered devices.
     */
    rc = ldi_open_by_name(IP6_DEV_NAME, FREAD | FWRITE, kcred, &Ip6DevHandle, DeviceIdent);
    ldi_ident_release(DeviceIdent);
    if (rc)
    {
        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: failed to open the IPv6 stream on '%s'.\n", pThis->szName));
        return VERR_INTNET_FLT_IF_FAILED;
    }

    /*
     * Obtain the interface flags from IPv6.
     */
    rc = vboxNetFltSolarisGetIfFlags(Ip6DevHandle, &Ip6Interface);
    if (RT_SUCCESS(rc))
    {
        /*
         * Open the UDP stream. We sort of cheat here and obtain the vnode so that we can perform
         * things that are not possible from the layered interface.
         */
        vnode_t *pUdp6VNode = NULL;
        vnode_t *pUdp6VNodeHeld = NULL;
        TIUSER *pUdp6User = NULL;
        rc = vboxNetFltSolarisOpenDev(UDP6_DEV_NAME, &pUdp6VNode, &pUdp6VNodeHeld, &pUdp6User);
        if (RT_SUCCESS(rc))
        {
            /*
             * Get the multiplexor IDs.
             */
            rc = ldi_ioctl(Ip6DevHandle, SIOCGLIFMUXID, (intptr_t)&Ip6Interface, FKIOCTL, kcred, &ret);
            if (!rc)
            {
                /*
                 * Get the multiplex file descriptor to the lower streams. Generally this is lost
                 * once a module is I_PLINK, we need to reobtain it for inserting/removing ourselves from the stack.
                 */
                int Ip6MuxFd;
                rc = vboxNetFltSolarisMuxIdToFd(pUdp6VNode, Ip6Interface.lifr_ip_muxid, &Ip6MuxFd);
                if (RT_SUCCESS(rc))
                {
                    /*
                     * We need to I_PUNLINK on these multiplexor IDs before we can start
                     * operating on the lower stream as insertions are direct operations on the lower stream.
                     */
                    int ret;
                    rc = strioctl(pUdp6VNode, I_PUNLINK, (intptr_t)Ip6Interface.lifr_ip_muxid, 0, K_TO_K, kcred, &ret);
                    if (!rc)
                    {
                        /*
                         * Obtain the vnode from the useless userland file descriptor.
                         */
                        file_t *pIpFile = getf(Ip6MuxFd);
                        if (   pIpFile
                            && pIpFile->f_vnode)
                        {
                            vnode_t *pIp6VNode = pIpFile->f_vnode;

                            /*
                             * Find the position on the host stack for attaching/detaching ourselves.
                             */
                            rc = vboxNetFltSolarisDetermineModPos(fAttach, pIp6VNode, &StrMod.pos);
                            if (RT_SUCCESS(rc))
                            {
                                /*
                                 * Set global data which will be grabbed by ModOpen.
                                 * There is a known (though very unlikely) race here because
                                 * of the inability to pass user data while inserting.
                                 */
                                g_VBoxNetFltSolarisInstance = pThis;
                                g_VBoxNetFltSolarisStreamType = kIp6Stream;

                                if (!fAttach)
                                    vboxNetFltRetain(pThis, false /* fBusy */);

                                /*
                                 * Inject/Eject from the host IPv6 stack.
                                 */
                                rc = strioctl(pIp6VNode, fAttach ? _I_INSERT : _I_REMOVE, (intptr_t)&StrMod, 0, K_TO_K,
                                            kcred, &ret);
                                if (!rc)
                                {
                                    g_VBoxNetFltSolarisInstance = NULL;
                                    g_VBoxNetFltSolarisStreamType = kUndefined;

                                    /*
                                     * Our job's not yet over; we need to relink the upper and lower streams
                                     * otherwise we've pretty much screwed up the host interface.
                                     */
                                    rc = vboxNetFltSolarisRelinkIp6(pUdp6VNode, &Ip6Interface, Ip6MuxFd);
                                    if (RT_SUCCESS(rc))
                                    {
                                        /*
                                         * Close the devices ONLY during the return from function case; otherwise
                                         * we end up close twice which is an instant kernel panic.
                                         */
                                        vboxNetFltSolarisCloseDev(pUdp6VNodeHeld, pUdp6User);
                                        ldi_close(Ip6DevHandle, FREAD | FWRITE, kcred);

                                        LogFlow((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: Success! %s %s@(IPv6:%d) "
                                                "%s interface %s\n", fAttach ? "Injected" : "Ejected", StrMod.mod_name,
                                                StrMod.pos, fAttach ? "to" : "from", pThis->szName));
                                        return VINF_SUCCESS;
                                    }
                                    else
                                    {
                                        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: Relinking failed. Mode=%s rc=%d.\n",
                                                fAttach ? "inject" : "eject", rc));
                                    }

                                    if (fAttach)
                                        strioctl(pIp6VNode, _I_REMOVE, (intptr_t)&StrMod, 0, K_TO_K, kcred, &ret);

                                    vboxNetFltSolarisRelinkIp6(pUdp6VNode, &Ip6Interface, Ip6MuxFd);
                                }
                                else
                                {
                                    LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: failed to %s the IP stack. rc=%d\n",
                                            fAttach ? "inject into" : "eject from", rc));
                                    if (!fAttach)
                                        vboxNetFltRelease(pThis, false /* fBusy */);
                                }
                            }
                            else
                                LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: failed to find position. rc=%d rc2=%d\n", rc, rc2));
                        }
                        else
                             LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: failed to get vnode from MuxFd.\n"));
                    }
                    else
                        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: failed to unlink upper stream rc=%d rc2=%d.\n", rc, rc2));
                }
                else
                    LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: failed to get MuxFd from MuxId. rc=%d rc2=%d\n"));
            }
            else
                LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: failed to get Mux Ids. rc=%d\n", rc));
            vboxNetFltSolarisCloseDev(pUdp6VNodeHeld, pUdp6User);
        }
        else
            LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: failed to open UDP. rc=%d\n", rc));
    }
    else
        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachIp6: failed to get IPv6 flags.\n", pThis->szName));

    ldi_close(Ip6DevHandle, FREAD | FWRITE, kcred);

    if (RT_SUCCESS(rc))
        return rc;

    return VERR_INTNET_FLT_IF_FAILED;
}


/**
 * Wrapper for attaching ourselves to the interface.
 *
 * @returns VBox status code.
 * @param   pThis           The instance.
 * @remarks Owns the globals mutex, so re-requesting it anytime during this phase
 *          would panic the system e.g. in vboxNetFltSolarisFindInstance).
 */
static int vboxNetFltSolarisAttachToInterface(PVBOXNETFLTINS pThis)
{
    int rc = vboxNetFltSolarisOpenStream(pThis);
    if (RT_SUCCESS(rc))
    {
        rc = vboxNetFltSolarisAttachIp4(pThis, true /* fAttach */);
        if (RT_SUCCESS(rc))
        {
            vboxNetFltSolarisAttachIp6(pThis, true /* fAttach */);
            /* Ignore Ipv6 binding errors as it's optional. */

            ASMAtomicWriteBool(&pThis->fDisconnectedFromHost, false);
        }
        else
            vboxNetFltSolarisCloseStream(pThis);
    }
    else
        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachToInterface vboxNetFltSolarisOpenStream failed rc=%Rrc\n", rc));

    return rc;
}


/**
 * Wrapper for detaching ourselves from the interface.
 *
 * @returns VBox status code.
 * @param   pThis           The instance.
 * @remarks Owns the globals mutex, so re-requesting it anytime during this phase
 *          would panic the system (e.g. in vboxNetFltSolarisFindInstance).
 */
static int vboxNetFltSolarisDetachFromInterface(PVBOXNETFLTINS pThis)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisDetachFromInterface pThis=%p\n", pThis));

    ASMAtomicWriteBool(&pThis->fDisconnectedFromHost, true);
    vboxNetFltSolarisCloseStream(pThis);
    int rc = vboxNetFltSolarisAttachIp4(pThis, false /* fAttach */);
    if (pThis->u.s.pvIp6Stream)
        rc = vboxNetFltSolarisAttachIp6(pThis, false /* fAttach */);

    return rc;
}


/**
 * Create a solaris message block from the SG list.
 *
 * @returns Solaris message block.
 * @param   pThis           The instance.
 * @param   pSG             Pointer to the scatter-gather list.
 */
static mblk_t *vboxNetFltSolarisMBlkFromSG(PVBOXNETFLTINS pThis, PINTNETSG pSG, uint32_t fDst)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisMBlkFromSG pThis=%p pSG=%p\n"));

    mblk_t *pMsg = allocb(pSG->cbTotal, BPRI_MED);
    if (RT_UNLIKELY(!pMsg))
    {
        LogRel((DEVICE_NAME ":vboxNetFltSolarisMBlkFromSG failed to alloc %d bytes for mblk_t.\n", pSG->cbTotal));
        return NULL;
    }

    /*
     * Single buffer copy. Maybe later explore the
     * need/possibility for using a mblk_t chain rather.
     */
    for (unsigned i = 0; i < pSG->cSegsUsed; i++)
    {
        if (pSG->aSegs[i].pv)
        {
            bcopy(pSG->aSegs[i].pv, pMsg->b_wptr, pSG->aSegs[i].cb);
            pMsg->b_wptr += pSG->aSegs[i].cb;
        }
    }
    DB_TYPE(pMsg) = M_DATA;
    return pMsg;
}


/**
 * Calculate the number of segments required for this message block.
 *
 * @returns Number of segments.
 * @param   pThis   The instance
 * @param   pMsg    Pointer to the data message.
 */
static unsigned vboxNetFltSolarisMBlkCalcSGSegs(PVBOXNETFLTINS pThis, mblk_t *pMsg)
{
    unsigned cSegs = 0;
    for (mblk_t *pCur = pMsg; pCur; pCur = pCur->b_cont)
        if (MBLKL(pCur))
            cSegs++;

#ifdef PADD_RUNT_FRAMES_FROM_HOST
    if (msgdsize(pMsg) < 60)
        cSegs++;
#endif

    NOREF(pThis);
    return RT_MAX(cSegs, 1);
}


/**
 * Initializes an SG list from the given message block.
 *
 * @returns VBox status code.
 * @param   pThis   The instance.
 * @param   pMsg    Pointer to the data message.
                    The caller must ensure it's not a control message block.
 * @param   pSG     Pointer to the SG.
 * @param   cSegs   Number of segments in the SG.
 *                  This should match the number in the message block exactly!
 * @param   fSrc    The source of the message.
 */
static int vboxNetFltSolarisMBlkToSG(PVBOXNETFLTINS pThis, mblk_t *pMsg, PINTNETSG pSG, unsigned cSegs, uint32_t fSrc)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisMBlkToSG pThis=%p pMsg=%p pSG=%p cSegs=%d\n", pThis, pMsg, pSG, cSegs));

    pSG->pvOwnerData = NULL;
    pSG->pvUserData = NULL;
    pSG->pvUserData2 = NULL;
    pSG->cUsers = 1;
    pSG->cbTotal = 0;
    pSG->fFlags = INTNETSG_FLAGS_TEMP;
    pSG->cSegsAlloc = cSegs;

    /*
     * Convert the message block to segments.
     */
    mblk_t *pCur = pMsg;
    unsigned iSeg = 0;
    while (pCur)
    {
        size_t cbSeg = MBLKL(pCur);
        if (cbSeg)
        {
            void *pvSeg = pCur->b_rptr;
            pSG->aSegs[iSeg].pv = pvSeg;
            pSG->aSegs[iSeg].cb = cbSeg;
            pSG->aSegs[iSeg].Phys = NIL_RTHCPHYS;
            pSG->cbTotal += cbSeg;
            iSeg++;
        }
        pCur = pCur->b_cont;
    }
    pSG->cSegsUsed = iSeg;

#ifdef PADD_RUNT_FRAMES_FROM_HOST
    if (pSG->cbTotal < 60 && (fSrc & INTNETTRUNKDIR_HOST))
    {
        LogFlow((DEVICE_NAME ":vboxNetFltSolarisMBlkToSG pulling up to length.\n"));

        static uint8_t const s_abZero[128] = {0};
        pSG->aSegs[iSeg].Phys = NIL_RTHCPHYS;
        pSG->aSegs[iSeg].pv = (void *)&s_abZero[0];
        pSG->aSegs[iSeg].cb = 60 - pSG->cbTotal;
        pSG->cbTotal = 60;
        pSG->cSegsUsed++;
    }
#endif

    LogFlow((DEVICE_NAME ":vboxNetFltSolarisMBlkToSG iSeg=%d pSG->cbTotal=%d msgdsize=%d\n", iSeg, pSG->cbTotal, msgdsize(pMsg)));
    return VINF_SUCCESS;
}


/**
 * Converts raw mode M_DATA messages to M_PROTO DL_UNITDATA_IND format.
 *
 * @returns VBox status code.
 * @param   pMsg        Pointer to the raw message.
 * @param   pDlpiMsg    Where to store the M_PROTO message.
 *
 * @remarks The original raw message would be no longer valid and will be
 *          linked as part of the new DLPI message. Callers must take care
 *          not to use the raw message if this routine is successful.
 */
static int vboxNetFltSolarisRawToUnitData(mblk_t *pMsg, mblk_t **ppDlpiMsg)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisRawToUnitData pMsg=%p\n", pMsg));

    if (DB_TYPE(pMsg) != M_DATA)
        return VERR_NO_MEMORY;

    size_t cbMsg = sizeof(dl_unitdata_ind_t) + 2 * sizeof(vboxnetflt_dladdr_t);
    mblk_t *pDlpiMsg = allocb(cbMsg, BPRI_MED);
    if (RT_UNLIKELY(!pDlpiMsg))
        return VERR_NO_MEMORY;

    DB_TYPE(pDlpiMsg) = M_PROTO;
    dl_unitdata_ind_t *pDlpiData = (dl_unitdata_ind_t *)pDlpiMsg->b_rptr;
    pDlpiData->dl_primitive = DL_UNITDATA_IND;
    pDlpiData->dl_dest_addr_length = VBOXNETFLT_DLADDRL;
    pDlpiData->dl_dest_addr_offset = sizeof(dl_unitdata_ind_t);
    pDlpiData->dl_src_addr_length = VBOXNETFLT_DLADDRL;
    pDlpiData->dl_src_addr_offset = VBOXNETFLT_DLADDRL + sizeof(dl_unitdata_ind_t);

    PRTNETETHERHDR pEthHdr = (PRTNETETHERHDR)pMsg->b_rptr;

    vboxnetflt_dladdr_t *pDlAddr = (vboxnetflt_dladdr_t *)(pDlpiMsg->b_rptr + pDlpiData->dl_dest_addr_offset);
    pDlAddr->SAP = RT_BE2H_U16(pEthHdr->EtherType);
    bcopy(&pEthHdr->DstMac, &pDlAddr->Mac, sizeof(RTMAC));

    pDlAddr = (vboxnetflt_dladdr_t *)(pDlpiMsg->b_rptr + pDlpiData->dl_src_addr_offset);
    pDlAddr->SAP = RT_BE2H_U16(pEthHdr->EtherType);
    bcopy(&pEthHdr->SrcMac, &pDlAddr->Mac, sizeof(RTMAC));

    pDlpiMsg->b_wptr = pDlpiMsg->b_rptr + cbMsg;

    /* Make the message point to the protocol header */
    pMsg->b_rptr += sizeof(RTNETETHERHDR);

    pDlpiMsg->b_cont = pMsg;
    *ppDlpiMsg = pDlpiMsg;
    return VINF_SUCCESS;
}


/**
 * Converts DLPI M_PROTO messages to the raw mode M_DATA format.
 *
 * @returns VBox status code.
 * @param   pMsg        Pointer to the M_PROTO message.
 * @param   ppRawMsg    Where to store the converted message.
 *
 * @remarks If successful, the original pMsg is no longer valid, it will be deleted.
 *          Callers must take care not to continue to use pMsg after a successful
 *          call to this conversion routine.
 */
static int vboxNetFltSolarisUnitDataToRaw(PVBOXNETFLTINS pThis, mblk_t *pMsg, mblk_t **ppRawMsg)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisUnitDataToRaw pMsg=%p\n", pMsg));

    if (   !pMsg->b_cont
        || DB_TYPE(pMsg) != M_PROTO)
    {
        LogRel((DEVICE_NAME ":vboxNetFltSolarisUnitDataToRaw invalid input message.\n"));
        return VERR_NET_PROTOCOL_ERROR;
    }

    /*
     * Upstream consumers send/receive packets in the fast path mode.
     * We of course need to convert them into raw ethernet frames.
     */
    RTNETETHERHDR EthHdr;
    union DL_primitives *pPrim = (union DL_primitives *)pMsg->b_rptr;
    switch (pPrim->dl_primitive)
    {
        case DL_UNITDATA_IND:
        {
            /*
             * Receive side.
             */
            dl_unitdata_ind_t *pDlpiMsg = (dl_unitdata_ind_t *)pMsg->b_rptr;
            bcopy(pMsg->b_rptr + pDlpiMsg->dl_dest_addr_offset, &EthHdr.DstMac, sizeof(EthHdr.DstMac));
            bcopy(pMsg->b_rptr + pDlpiMsg->dl_src_addr_offset, &EthHdr.SrcMac, sizeof(EthHdr.SrcMac));

            vboxnetflt_dladdr_t *pDLSapAddr = (vboxnetflt_dladdr_t *)(pMsg->b_rptr + pDlpiMsg->dl_dest_addr_offset);
            EthHdr.EtherType = RT_H2BE_U16(pDLSapAddr->SAP);

            break;
        }

        case DL_UNITDATA_REQ:
        {
            /*
             * Send side.
             */
            dl_unitdata_req_t *pDlpiMsg = (dl_unitdata_req_t *)pMsg->b_rptr;

            bcopy(pMsg->b_rptr + pDlpiMsg->dl_dest_addr_offset, &EthHdr.DstMac, sizeof(EthHdr.DstMac));
            bcopy(&pThis->u.s.Mac, &EthHdr.SrcMac, sizeof(EthHdr.SrcMac));

            vboxnetflt_dladdr_t *pDLSapAddr = (vboxnetflt_dladdr_t *)(pMsg->b_rptr + pDlpiMsg->dl_dest_addr_offset);
            EthHdr.EtherType = RT_H2BE_U16(pDLSapAddr->SAP);

            break;
        }

        default:
        {
            LogRel((DEVICE_NAME ":vboxNetFltSolarisUnitDataToRaw Unknown M_PROTO. This shouldn't be happening!!"));
            return VERR_NET_PROTOCOL_ERROR;
        }
    }

    /*
     * Let us just link it as a mblk_t chain rather than re-copy the entire message.
     * The vboxNetFltSolarisMBlkToSG function will handle chained mblk_t's.
     */
    size_t cbLen = sizeof(EthHdr);
    mblk_t *pEtherMsg = allocb(cbLen, BPRI_MED);
    if (RT_UNLIKELY(!pEtherMsg))
        return VERR_NO_MEMORY;

    DB_TYPE(pEtherMsg) = M_DATA;
    bcopy(&EthHdr, pEtherMsg->b_wptr, sizeof(EthHdr));
    pEtherMsg->b_wptr += cbLen;

    pEtherMsg->b_cont = pMsg->b_cont;

    /*
     * Change the chained blocks to type M_DATA.
     */
    for (mblk_t *pTmp = pEtherMsg->b_cont; pTmp; pTmp = pTmp->b_cont)
        DB_TYPE(pTmp) = M_DATA;

    pMsg->b_cont = NULL;
    freemsg(pMsg);

    *ppRawMsg = pEtherMsg;
    return VINF_SUCCESS;
}


/**
 * Initializes a packet identifier.
 *
 * @param   pTag        Pointer to the packed identifier.
 * @param   pMsg        Pointer to the message to be identified.
 *
 * @remarks Warning!!! This function assumes 'pMsg' is an unchained message.
 */
static inline void vboxNetFltSolarisInitPacketId(PVBOXNETFLTPACKETID pTag, mblk_t *pMsg)
{
    PCRTNETETHERHDR pEthHdr = (PCRTNETETHERHDR)pMsg->b_rptr;
    size_t cbMsg = MBLKL(pMsg);

    pTag->cbPacket = cbMsg;
    pTag->Checksum = RTCrc32(pMsg->b_rptr, cbMsg);
    bcopy(&pEthHdr->SrcMac, &pTag->SrcMac, sizeof(RTMAC));
    bcopy(&pEthHdr->DstMac, &pTag->DstMac, sizeof(RTMAC));
}


/**
 * Queues a packet for loopback elimination.
 *
 * @returns VBox status code.
 * @param   pThis               The instance.
 * @param   pPromiscStream      Pointer to the promiscuous stream.
 * @param   pMsg                Pointer to the message.
 * @remarks Warning!! Assumes caller has taken care of any locking necessary.
 */
static int vboxNetFltSolarisQueueLoopback(PVBOXNETFLTINS pThis, vboxnetflt_promisc_stream_t *pPromiscStream, mblk_t *pMsg)
{
    Assert(pThis);
    Assert(pMsg);
    Assert(DB_TYPE(pMsg) == M_DATA);
    Assert(pPromiscStream);

    LogFlow((DEVICE_NAME ":vboxNetFltSolarisQueueLoopback pThis=%p pPromiscStream=%p pMsg=%p\n", pThis, pPromiscStream, pMsg));

    if (RT_UNLIKELY(pMsg->b_cont))
    {
        /*
         * We don't currently make chained messages in on Xmit
         * so this only needs to be supported when we do that.
         */
        return VERR_NOT_SUPPORTED;
    }

    size_t cbMsg = MBLKL(pMsg);
    if (RT_UNLIKELY(cbMsg < sizeof(RTNETETHERHDR)))
        return VERR_NET_MSG_SIZE;

    int rc = RTSemFastMutexRequest(pThis->u.s.hFastMtx);
    AssertRCReturn(rc, rc);

    PVBOXNETFLTPACKETID pCur = NULL;
    if (pPromiscStream->cLoopback < VBOXNETFLT_LOOPBACK_SIZE
        || (   pPromiscStream->pHead
            && pPromiscStream->pHead->cbPacket == 0))
    {
        do
        {
            if (!pPromiscStream->pHead)
            {
                pCur = RTMemAlloc(sizeof(VBOXNETFLTPACKETID));
                if (RT_UNLIKELY(!pCur))
                {
                    rc = VERR_NO_MEMORY;
                    break;
                }

                vboxNetFltSolarisInitPacketId(pCur, pMsg);

                pCur->pNext = NULL;
                pPromiscStream->pHead = pCur;
                pPromiscStream->pTail = pCur;
                pPromiscStream->cLoopback++;

                LogFlow((DEVICE_NAME ":vboxNetFltSolarisQueueLoopback initialized head. checksum=%u.\n",
                        pPromiscStream->pHead->Checksum));
                break;
            }
            else if (   pPromiscStream->pHead
                     && pPromiscStream->pHead->cbPacket == 0)
            {
                pCur = pPromiscStream->pHead;
                vboxNetFltSolarisInitPacketId(pCur, pMsg);

                LogFlow((DEVICE_NAME ":vboxNetFltSolarisQueueLoopback re-used head checksum=%u cLoopback=%d.\n",
                        pCur->Checksum, pPromiscStream->cLoopback));
                break;
            }
            else
            {
                pCur = RTMemAlloc(sizeof(VBOXNETFLTPACKETID));
                if (RT_UNLIKELY(!pCur))
                {
                    rc = VERR_NO_MEMORY;
                    break;
                }

                vboxNetFltSolarisInitPacketId(pCur, pMsg);

                pCur->pNext = pPromiscStream->pHead;
                pPromiscStream->pHead = pCur;
                pPromiscStream->cLoopback++;

                LogFlow((DEVICE_NAME ":vboxNetFltSolarisQueueLoopback added head checksum=%u cLoopback=%d.\n", pCur->Checksum,
                        pPromiscStream->cLoopback));
                break;
            }
        } while (0);
    }
    else
    {
        /*
         * Maximum loopback queue size reached. Re-use tail as head.
         */
        Assert(pPromiscStream->pHead);
        Assert(pPromiscStream->pTail);

        /*
         * Find tail's previous item.
         */
        PVBOXNETFLTPACKETID pPrev = NULL;
        pCur = pPromiscStream->pHead;

        /** @todo consider if this is worth switching to a double linked list... */
        while (pCur != pPromiscStream->pTail)
        {
            pPrev = pCur;
            pCur = pCur->pNext;
        }

        pPromiscStream->pTail = pPrev;
        pPromiscStream->pTail->pNext = NULL;
        pCur->pNext = pPromiscStream->pHead;
        pPromiscStream->pHead = pCur;

        vboxNetFltSolarisInitPacketId(pCur, pMsg);
        LogFlow((DEVICE_NAME ":vboxNetFltSolarisQueueLoopback recycled tail!! checksum=%u cLoopback=%d\n", pCur->Checksum,
                pPromiscStream->cLoopback));
    }

    RTSemFastMutexRelease(pThis->u.s.hFastMtx);

    return rc;
}


/**
 * Checks if the packet is enqueued for loopback as our own packet.
 *
 * @returns If it's our packet, returns true after dequeuing it, otherwise false.
 * @param   pThis               The instance.
 * @param   pPromiscStream      Pointer to the promiscuous stream.
 * @param   pMsg                Pointer to the message.
 */
static bool vboxNetFltSolarisIsOurMBlk(PVBOXNETFLTINS pThis, vboxnetflt_promisc_stream_t *pPromiscStream, mblk_t *pMsg)
{
    Assert(pThis);
    Assert(pPromiscStream);
    Assert(pMsg);
    Assert(DB_TYPE(pMsg) == M_DATA);

    LogFlow((DEVICE_NAME ":vboxNetFltSolarisIsOurMBlk pThis=%p pMsg=%p\n", pThis, pMsg));

    if (pMsg->b_cont)
    {
        /** Handle this when Xmit makes chained messages */
        return false;
    }

    size_t cbMsg = MBLKL(pMsg);
    if (cbMsg < sizeof(RTNETETHERHDR))
        return false;

    int rc = RTSemFastMutexRequest(pThis->u.s.hFastMtx);
    AssertRCReturn(rc, rc);

    PVBOXNETFLTPACKETID pPrev = NULL;
    PVBOXNETFLTPACKETID pCur = pPromiscStream->pHead;
    bool fIsOurPacket = false;
    while (pCur)
    {
        PCRTNETETHERHDR pEthHdr = (PCRTNETETHERHDR)pMsg->b_rptr;
        if (   pCur->cbPacket != cbMsg
            || pCur->SrcMac.au8[0] != pEthHdr->SrcMac.au8[0]
            || pCur->SrcMac.au8[1] != pEthHdr->SrcMac.au8[1]
            || pCur->SrcMac.au8[2] != pEthHdr->SrcMac.au8[2]
            || pCur->SrcMac.au8[3] != pEthHdr->SrcMac.au8[3]
            || pCur->SrcMac.au8[4] != pEthHdr->SrcMac.au8[4]
            || pCur->SrcMac.au8[5] != pEthHdr->SrcMac.au8[5]
            || pCur->DstMac.au8[0] != pEthHdr->DstMac.au8[0]
            || pCur->DstMac.au8[1] != pEthHdr->DstMac.au8[1]
            || pCur->DstMac.au8[2] != pEthHdr->DstMac.au8[2]
            || pCur->DstMac.au8[3] != pEthHdr->DstMac.au8[3]
            || pCur->DstMac.au8[4] != pEthHdr->DstMac.au8[4]
            || pCur->DstMac.au8[5] != pEthHdr->DstMac.au8[5])
        {
            pPrev = pCur;
            pCur = pCur->pNext;
            continue;
        }

        uint16_t Checksum = RTCrc32(pMsg->b_rptr, cbMsg);
        if (pCur->Checksum != Checksum)
        {
            pPrev = pCur;
            pCur = pCur->pNext;
            continue;
        }

        /*
         * Yes, it really is our own packet, mark it as handled
         * and move it as a "free slot" to the head and return success.
         */
        pCur->cbPacket = 0;
        if (pPrev)
        {
            if (!pCur->pNext)
                pPromiscStream->pTail = pPrev;

            pPrev->pNext = pCur->pNext;
            pCur->pNext = pPromiscStream->pHead;
            pPromiscStream->pHead = pCur;
        }
        fIsOurPacket = true;

        LogFlow((DEVICE_NAME ":vboxNetFltSolarisIsOurMBlk found packet %p Checksum=%u cLoopback=%d\n", pMsg, Checksum,
                    pPromiscStream->cLoopback));
        break;
    }

    RTSemFastMutexRelease(pThis->u.s.hFastMtx);
    return fIsOurPacket;
}


/**
 * Worker for routing messages from the wire or from the host.
 *
 * @returns VBox status code.
 * @param   pThis       The instance.
 * @param   pStream     Pointer to the stream.
 * @param   pQueue      Pointer to the queue.
 * @param   pOrigMsg    Pointer to the message.
 */
static int vboxNetFltSolarisRecv(PVBOXNETFLTINS pThis, vboxnetflt_stream_t *pStream, queue_t *pQueue, mblk_t *pMsg)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisRecv pThis=%p pMsg=%p\n", pThis, pMsg));

    AssertCompile(sizeof(struct ether_header) == sizeof(RTNETETHERHDR));
    Assert(pStream->Type == kPromiscStream);

    vboxnetflt_promisc_stream_t *pPromiscStream = ASMAtomicUoReadPtr((void * volatile *)&pThis->u.s.pvPromiscStream);
    if (RT_UNLIKELY(!pPromiscStream))
    {
        freemsg(pMsg);
        LogRel((DEVICE_NAME ":Promiscuous stream missing!! Failing to receive packet.\n"));
        return VERR_INVALID_POINTER;
    }

    /*
     * Don't loopback packets we transmit to the wire.
     */
    /** @todo maybe we need not check for loopback for INTNETTRUNKDIR_HOST case? */
    if (vboxNetFltSolarisIsOurMBlk(pThis, pPromiscStream, pMsg))
    {
        LogFlow((DEVICE_NAME ":Avoiding packet loopback.\n"));
        freemsg(pMsg);
        return VINF_SUCCESS;
    }

    /*
     * Figure out the source of the packet based on the source Mac address.
     */
    uint32_t fSrc = INTNETTRUNKDIR_WIRE;
    PRTNETETHERHDR pEthHdr = (PRTNETETHERHDR)pMsg->b_rptr;
    if (vboxNetFltPortOsIsHostMac(pThis, &pEthHdr->SrcMac))
        fSrc = INTNETTRUNKDIR_HOST;

    /*
     * Afaik; we no longer need to worry about incorrect checksums because we now use
     * a dedicated stream and don't intercept packets under IP/ARP which might be doing
     * checksum offloading.
     */
#if 0
    if (fSrc & INTNETTRUNKDIR_HOST)
    {
        mblk_t *pCorrectedMsg = vboxNetFltSolarisFixChecksums(pMsg);
        if (pCorrectedMsg)
            pMsg = pCorrectedMsg;
    }
    vboxNetFltSolarisAnalyzeMBlk(pMsg);
#endif

    /*
     * Route all received packets into the internal network.
     */
    unsigned cSegs = vboxNetFltSolarisMBlkCalcSGSegs(pThis, pMsg);
    PINTNETSG pSG = (PINTNETSG)alloca(RT_OFFSETOF(INTNETSG, aSegs[cSegs]));
    int rc = vboxNetFltSolarisMBlkToSG(pThis, pMsg, pSG, cSegs, fSrc);
    if (RT_SUCCESS(rc))
        pThis->pSwitchPort->pfnRecv(pThis->pSwitchPort, pSG, fSrc);
    else
        LogRel((DEVICE_NAME ":vboxNetFltSolarisMBlkToSG failed. rc=%d\n", rc));

    freemsg(pMsg);
    return VINF_SUCCESS;
}


/**
 * Find the PVBOXNETFLTINS associated with a stream.
 *
 * @returns PVBOXNETFLTINS instance, or NULL if there's none.
 * @param   pStream     Pointer to the stream to search for.
 */
static PVBOXNETFLTINS vboxNetFltSolarisFindInstance(vboxnetflt_stream_t *pStream)
{
    if (!pStream)
        return NULL;

    vboxnetflt_stream_t *pCur = g_VBoxNetFltSolarisStreams;
    for (; pCur; pCur = pCur->pNext)
        if (pCur == pStream)
            return pCur->pThis;

    return NULL;
}


/**
 * Finalize the message to be fed into the internal network.
 * Verifies and tries to fix checksums for TCP, UDP and IP.
 *
 * @returns Corrected message or NULL if no change was required.
 * @param   pMsg    Pointer to the message block.
 *                  This must not be DLPI linked messages, must be M_DATA.
 *
 * @remarks If this function returns a checksum adjusted message, the
 *          passed in input message has been freed and should not be
 *          referenced anymore by the caller.
 */
static mblk_t *vboxNetFltSolarisFixChecksums(mblk_t *pMsg)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisFixChecksums pMsg=%p\n"));

    Assert(DB_TYPE(pMsg) == M_DATA);

    if (MBLKL(pMsg) < sizeof(RTNETETHERHDR))
    {
        LogRel((DEVICE_NAME ":vboxNetFltSolarisFixChecksums Packet shorter than ethernet header size!\n"));
        return NULL;
    }

    PRTNETETHERHDR pEthHdr = (PRTNETETHERHDR)pMsg->b_rptr;
    if (pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_IPV4))
    {
        /*
         * Check if we have a complete packet or being fed a chain.
         */
        size_t cbIpPacket = 0;
        mblk_t *pFullMsg = NULL;
        if (pMsg->b_cont)
        {
            LogFlow((DEVICE_NAME ":Chained mblk_t.\n"));

            /*
             * Handle chain by making a packet copy to verify if the IP checksum is correct.
             * Contributions to calculating IP checksums from a chained message block with
             * odd/non-pulled up sizes are welcome.
             */
            size_t cbFullMsg = msgdsize(pMsg);
            mblk_t *pFullMsg = allocb(cbFullMsg, BPRI_MED);
            LogFlow((DEVICE_NAME ":msgdsize returns %d\n", cbFullMsg));
            if (RT_UNLIKELY(!pFullMsg))
            {
                LogRel((DEVICE_NAME ":vboxNetFltSolarisFixChecksums failed to alloc new message of %d bytes.\n", cbFullMsg));
                return NULL;
            }

            for (mblk_t *pTmp = pMsg; pTmp; pTmp = pTmp->b_cont)
            {
                if (DB_TYPE(pTmp) == M_DATA)
                {
                    bcopy(pTmp->b_rptr, pFullMsg->b_wptr, MBLKL(pTmp));
                    pFullMsg->b_wptr += MBLKL(pTmp);
                }
            }

            DB_TYPE(pFullMsg) = M_DATA;
            pEthHdr = (PRTNETETHERHDR)pFullMsg->b_rptr;
            cbIpPacket = MBLKL(pFullMsg) - sizeof(RTNETETHERHDR);
        }
        else
            cbIpPacket = MBLKL(pMsg) - sizeof(RTNETETHERHDR);

        /*
         * Check if the IP checksum is valid.
         */
        uint8_t *pbProtocol = (uint8_t *)(pEthHdr + 1);
        PRTNETIPV4 pIpHdr = (PRTNETIPV4)pbProtocol;
        size_t cbPayload = cbIpPacket - (pIpHdr->ip_hl << 2);
        bool fChecksumAdjusted = false;
        if (RTNetIPv4IsHdrValid(pIpHdr, cbPayload, cbPayload))
        {
            pbProtocol += (pIpHdr->ip_hl << 2);

            /*
             * Fix up TCP/UDP and IP checksums if they're incomplete/invalid.
             */
            if (pIpHdr->ip_p == RTNETIPV4_PROT_TCP)
            {
                PRTNETTCP pTcpHdr = (PRTNETTCP)pbProtocol;
                uint16_t TcpChecksum = RTNetIPv4TCPChecksum(pIpHdr, pTcpHdr, NULL);
                if (pTcpHdr->th_sum != TcpChecksum)
                {
                    pTcpHdr->th_sum = TcpChecksum;
                    fChecksumAdjusted = true;
                    LogFlow((DEVICE_NAME ":fixed TCP checksum.\n"));
                }
            }
            else if (pIpHdr->ip_p == RTNETIPV4_PROT_UDP)
            {
                PRTNETUDP pUdpHdr = (PRTNETUDP)pbProtocol;
                uint16_t UdpChecksum = RTNetIPv4UDPChecksum(pIpHdr, pUdpHdr, pUdpHdr + 1);

                if (pUdpHdr->uh_sum != UdpChecksum)
                {
                    pUdpHdr->uh_sum = UdpChecksum;
                    fChecksumAdjusted = true;
                    LogFlow((DEVICE_NAME ":Fixed UDP checksum."));
                }
            }
        }

        if (fChecksumAdjusted)
        {
            /*
             * If we made a copy and the checksum is corrected on the copy,
             * free the original, return the checksum fixed copy.
             */
            if (pFullMsg)
            {
                freemsg(pMsg);
                return pFullMsg;
            }

            return pMsg;
        }

        /*
         * If we made a copy and the checksum is NOT corrected, free the copy,
         * and return NULL.
         */
        if (pFullMsg)
            freemsg(pFullMsg);

        return NULL;
    }

    return NULL;
}


/**
 * Simple packet dump, used for internal debugging.
 *
 * @param   pMsg    Pointer to the message to analyze and dump.
 */
static void vboxNetFltSolarisAnalyzeMBlk(mblk_t *pMsg)
{
    LogFlow((DEVICE_NAME ":vboxNetFltSolarisAnalyzeMBlk pMsg=%p\n", pMsg));

    PCRTNETETHERHDR pEthHdr = (PCRTNETETHERHDR)pMsg->b_rptr;
    uint8_t *pb = pMsg->b_rptr;
    if (pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_IPV4))
    {
        PRTNETIPV4 pIpHdr = (PRTNETIPV4)(pEthHdr + 1);
        size_t cbLen = MBLKL(pMsg) - sizeof(*pEthHdr);
        if (!pMsg->b_cont)
        {
            if (pIpHdr->ip_p == RTNETIPV4_PROT_ICMP)
                LogFlow((DEVICE_NAME ":ICMP D=%.6Rhxs  S=%.6Rhxs  T=%04x\n", pb, pb + 6, RT_BE2H_U16(*(uint16_t *)(pb + 12))));
            else if (pIpHdr->ip_p == RTNETIPV4_PROT_TCP)
                LogFlow((DEVICE_NAME ":TCP D=%.6Rhxs  S=%.6Rhxs\n", pb, pb + 6));
            else if (pIpHdr->ip_p == RTNETIPV4_PROT_UDP)
            {
                PCRTNETUDP pUdpHdr = (PCRTNETUDP)((uint32_t *)pIpHdr + pIpHdr->ip_hl);
                if (   RT_BE2H_U16(pUdpHdr->uh_sport) == 67
                    && RT_BE2H_U16(pUdpHdr->uh_dport) == 68)
                {
                    LogRel((DEVICE_NAME ":UDP bootp ack D=%.6Rhxs S=%.6Rhxs UDP_CheckSum=%04x Computex=%04x\n", pb, pb + 6,
                                RT_BE2H_U16(pUdpHdr->uh_sum), RT_BE2H_U16(RTNetIPv4UDPChecksum(pIpHdr, pUdpHdr, pUdpHdr + 1))));
                }
            }
        }
        else
        {
            LogFlow((DEVICE_NAME ":Chained IP packet. Skipping validity check.\n"));
        }
    }
    else if (pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_ARP))
    {
        PRTNETARPHDR pArpHdr = (PRTNETARPHDR)(pEthHdr + 1);
        LogFlow((DEVICE_NAME ":ARP Op=%d\n", pArpHdr->ar_oper));
    }
    else if (pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_IPV6))
    {
        LogFlow((DEVICE_NAME ":IPv6 D=%.6Rhxs S=%.6Rhxs\n", pb, pb + 6));
    }
    else if (pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_IPX_1)
             || pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_IPX_2)
             || pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_IPX_3))
    {
        LogFlow((DEVICE_NAME ":IPX packet.\n"));
    }
    else
    {
        LogFlow((DEVICE_NAME ":Unknown EtherType=%x D=%.6Rhxs S=%.6Rhxs\n", RT_H2BE_U16(pEthHdr->EtherType), &pEthHdr->DstMac,
                    &pEthHdr->SrcMac));
        /* LogFlow((DEVICE_NAME ":%.*Rhxd\n", MBLKL(pMsg), pMsg->b_rptr)); */
    }
}


/* -=-=-=-=-=- Common Hooks -=-=-=-=-=- */
bool vboxNetFltPortOsIsPromiscuous(PVBOXNETFLTINS pThis)
{
    /*
     * There is no easy way of obtaining the global host side promiscuous counter.
     * Currently we just return false.
     */
    return false;
}


void vboxNetFltPortOsGetMacAddress(PVBOXNETFLTINS pThis, PRTMAC pMac)
{
    LogFlow((DEVICE_NAME ":vboxNetFltPortOsGetMacAddress pThis=%p\n", pThis));
    *pMac = pThis->u.s.Mac;
}


bool vboxNetFltPortOsIsHostMac(PVBOXNETFLTINS pThis, PCRTMAC pMac)
{
    /*
     * MAC address change acknowledgements are intercepted on the read side
     * hence theoritically we are always update to date with any changes.
     */
    return pThis->u.s.Mac.au16[0] == pMac->au16[0]
        && pThis->u.s.Mac.au16[1] == pMac->au16[1]
        && pThis->u.s.Mac.au16[2] == pMac->au16[2];
}


void vboxNetFltPortOsSetActive(PVBOXNETFLTINS pThis, bool fActive)
{
    LogFlow((DEVICE_NAME ":vboxNetFltPortOsSetActive pThis=%p fActive=%d\n", pThis, fActive));

    /*
     * Enable/disable promiscuous mode.
     */
    vboxnetflt_stream_t *pStream = ASMAtomicUoReadPtr((void * volatile *)&pThis->u.s.pvPromiscStream);
    if (pStream)
    {
        if (pStream->pReadQueue)
        {
            int rc = vboxNetFltSolarisPromiscReq(pStream->pReadQueue, fActive);
            if (RT_FAILURE(rc))
                LogRel((DEVICE_NAME ":vboxNetFltPortOsSetActive failed to request promiscuous mode! rc=%d\n", rc));
        }
        else
            LogRel((DEVICE_NAME ":vboxNetFltPortOsSetActive queue not found!\n"));
    }
    else
        LogRel((DEVICE_NAME ":vboxNetFltPortOsSetActive stream not found!\n"));
}


int vboxNetFltOsDisconnectIt(PVBOXNETFLTINS pThis)
{
    LogFlow((DEVICE_NAME ":vboxNetFltOsDisconnectIt pThis=%p\n", pThis));

    vboxNetFltSolarisDetachFromInterface(pThis);

    if (pThis->u.s.hFastMtx != NIL_RTSEMFASTMUTEX)
    {
        RTSemFastMutexDestroy(pThis->u.s.hFastMtx);
        pThis->u.s.hFastMtx = NIL_RTSEMFASTMUTEX;
    }
    return VINF_SUCCESS;
}


int  vboxNetFltOsConnectIt(PVBOXNETFLTINS pThis)
{
    /* Nothing to do here. */
    return VINF_SUCCESS;
}


void vboxNetFltOsDeleteInstance(PVBOXNETFLTINS pThis)
{
    LogFlow((DEVICE_NAME ":vboxNetFltOsDeleteInstance pThis=%p\n", pThis));
    /* Nothing to do here. */
}


int vboxNetFltOsInitInstance(PVBOXNETFLTINS pThis)
{
    LogFlow((DEVICE_NAME ":vboxNetFltOsInitInstance pThis=%p\n"));

    /*
     * Mutex used for loopback lockouts.
     */
    int rc = RTSemFastMutexCreate(&pThis->u.s.hFastMtx);
    if (RT_SUCCESS(rc))
    {
        rc = vboxNetFltSolarisAttachToInterface(pThis);
        if (RT_SUCCESS(rc))
            return rc;

        LogRel((DEVICE_NAME ":vboxNetFltSolarisAttachToInterface failed. rc=%Rrc\n", rc));
        RTSemFastMutexDestroy(pThis->u.s.hFastMtx);
        pThis->u.s.hFastMtx = NIL_RTSEMFASTMUTEX;
    }

    return rc;
}


int vboxNetFltOsPreInitInstance(PVBOXNETFLTINS pThis)
{
    /*
     * Init. the solaris specific data.
     */
    pThis->u.s.pvIp4Stream = NULL;
    pThis->u.s.pvIp6Stream = NULL;
    pThis->u.s.pvArpStream = NULL;
    pThis->u.s.pvPromiscStream = NULL;
    pThis->u.s.hFastMtx = NIL_RTSEMFASTMUTEX;
    bzero(&pThis->u.s.Mac, sizeof(pThis->u.s.Mac));
    return VINF_SUCCESS;
}


bool vboxNetFltOsMaybeRediscovered(PVBOXNETFLTINS pThis)
{
    /*
     * We don't support interface rediscovery on Solaris hosts because the
     * filter is very tightly bound to the stream.
     */
    return false;
}


int vboxNetFltPortOsXmit(PVBOXNETFLTINS pThis, PINTNETSG pSG, uint32_t fDst)
{
    LogFlow((DEVICE_NAME ":vboxNetFltPortOsXmit pThis=%p pSG=%p fDst=%d\n", pThis, pSG, fDst));

    int rc = VINF_SUCCESS;
    if (fDst & INTNETTRUNKDIR_WIRE)
    {
#ifdef VBOXNETFLT_SOLARIS_USE_NETINFO
        /*
         * @todo try find a way for IPFilter to accept ethernet frames (currently silently drops them).
         */
        mblk_t *pMsg = vboxNetFltSolarisMBlkFromSG(pThis, pSG, fDst);
        if (RT_LIKELY(pMsg))
        {
            PCRTNETETHERHDR pEthHdr = (PCRTNETETHERHDR)pMsg->b_rptr;
            unsigned uProtocol;
            if (pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_IPV6))
                uProtocol = AF_INET6;
            else if (pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_IPV4))
                uProtocol = AF_INET;

            /*
             * Queue out using netinfo.
             */
            netstack_t *pNetStack = netstack_get_current();
            if (pNetStack)
            {
                net_data_t pNetData = net_lookup_impl(NHF_INET, pNetStack);
                if (pNetData)
                {
                    phy_if_t pInterface = net_phylookup(pNetData, pThis->szName);
                    if (pInterface)
                    {
                        net_inject_t InjectData;
                        InjectData.ni_packet = pMsg;
                        InjectData.ni_physical = pInterface;
                        bzero(&InjectData.ni_addr, sizeof(InjectData.ni_addr));
                        InjectData.ni_addr.ss_family = uProtocol;

                        /*
                         * Queue out rather than direct out transmission.
                         */
                        int rc = net_inject(pNetData, NI_QUEUE_OUT, &InjectData);
                        if (!rc)
                            rc = VINF_SUCCESS;
                        else
                        {
                            LogRel((DEVICE_NAME ":queuing IP packet for transmission failed. rc=%d\n", rc));
                            rc = VERR_NET_IO_ERROR;
                        }
                    }
                    else
                    {
                        LogRel((DEVICE_NAME ":vboxNetFltPortOsXmit failed to lookup physical interface.\n"));
                        rc = VERR_NET_IO_ERROR;
                    }
                }
                else
                {
                    LogRel((DEVICE_NAME ":vboxNetFltPortOsXmit failed to get IP hooks.\n"));
                    rc = VERR_NET_IO_ERROR;
                }
                netstack_rele(pNetStack);
            }
            else
            {
                LogRel((DEVICE_NAME ":vboxNetFltPortOsXmit failed to get current net stack.\n"));
                rc = VERR_NET_IO_ERROR;
            }
        }
        else
        {
            LogRel((DEVICE_NAME ":vboxNetFltPortOsXmit vboxNetFltSolarisMBlkFromSG failed.\n"));
            rc = VERR_NO_MEMORY;
        }
#else
        vboxnetflt_promisc_stream_t *pPromiscStream = ASMAtomicUoReadPtr((void * volatile *)&pThis->u.s.pvPromiscStream);
        if (RT_LIKELY(pPromiscStream))
        {
            mblk_t *pMsg = vboxNetFltSolarisMBlkFromSG(pThis, pSG, fDst);
            if (RT_LIKELY(pMsg))
            {
                LogFlow((DEVICE_NAME ":vboxNetFltPortOsXmit INTNETTRUNKDIR_WIRE\n"));

                vboxNetFltSolarisQueueLoopback(pThis, pPromiscStream, pMsg);
                putnext(WR(pPromiscStream->Stream.pReadQueue), pMsg);
            }
            else
            {
                LogRel((DEVICE_NAME ":vboxNetFltPortOsXmit vboxNetFltSolarisMBlkFromSG failed.\n"));
                rc = VERR_NO_MEMORY;
            }
        }
#endif
    }

    if (fDst & INTNETTRUNKDIR_HOST)
    {
        /*
         * For unplumbed interfaces we would not be bound to IP or ARP.
         * We either bind to both or neither; so atomic reading one should be sufficient.
         */
        vboxnetflt_stream_t *pIp4Stream  = ASMAtomicUoReadPtr((void * volatile *)&pThis->u.s.pvIp4Stream);
        if (!pIp4Stream)
            return rc;

        /*
         * Create a message block and send it up the host stack (upstream).
         */
        mblk_t *pMsg = vboxNetFltSolarisMBlkFromSG(pThis, pSG, fDst);
        if (RT_LIKELY(pMsg))
        {
            PCRTNETETHERHDR pEthHdr = (PCRTNETETHERHDR)pMsg->b_rptr;

            /*
             * Send message up ARP stream.
             */
            if (pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_ARP))
            {
                LogFlow((DEVICE_NAME ":vboxNetFltPortOsXmit INTNETTRUNKDIR_HOST ARP\n"));

                vboxnetflt_stream_t *pArpStream = ASMAtomicUoReadPtr((void * volatile *)&pThis->u.s.pvArpStream);
                if (pArpStream)
                {
                    /*
                     * Construct a DL_UNITDATA_IND style message for ARP as it doesn't understand fast path.
                     */
                    mblk_t *pDlpiMsg;
                    int rc = vboxNetFltSolarisRawToUnitData(pMsg, &pDlpiMsg);
                    if (RT_SUCCESS(rc))
                    {
                        pMsg = pDlpiMsg;

                        queue_t *pArpReadQueue = pArpStream->pReadQueue;
                        putnext(pArpReadQueue, pMsg);
                    }
                    else
                    {
                        LogRel((DEVICE_NAME ":vboxNetFltSolarisRawToUnitData failed!\n"));
                        freemsg(pMsg);
                        rc = VERR_NO_MEMORY;
                    }
                }
                else
                    freemsg(pMsg);  /* Should really never happen... */
            }
            else
            {
                 vboxnetflt_stream_t *pIp6Stream  = ASMAtomicUoReadPtr((void * volatile *)&pThis->u.s.pvIp6Stream);
                 if (   pEthHdr->EtherType == RT_H2BE_U16(RTNET_ETHERTYPE_IPV6)
                     && pIp6Stream)
                 {
                     /*
                      * Send messages up IPv6 stream.
                      */
                     LogFlow((DEVICE_NAME ":vboxNetFltPortOsXmit INTNETTRUNKDIR_HOST IPv6\n"));

                     pMsg->b_rptr += sizeof(RTNETETHERHDR);
                     queue_t *pIp6ReadQueue = pIp6Stream->pReadQueue;
                     putnext(pIp6ReadQueue, pMsg);
                 }
                 else
                 {
                    /*
                     * Send messages up IPv4 stream.
                     */
                    LogFlow((DEVICE_NAME ":vboxNetFltPortOsXmit INTNETTRUNKDIR_HOST IPv4\n"));

                    pMsg->b_rptr += sizeof(RTNETETHERHDR);
                    queue_t *pIp4ReadQueue = pIp4Stream->pReadQueue;
                    putnext(pIp4ReadQueue, pMsg);
                }
            }
        }
        else
        {
            LogRel((DEVICE_NAME ":vboxNetFltSolarisMBlkFromSG failed.\n"));
            rc = VERR_NO_MEMORY;
        }
    }

    return rc;
}