xen/io/xnbu.c

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

/*
 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Xen inter-domain backend - GLDv3 driver edition.
 *
 * A traditional GLDv3 driver used to communicate with a guest
 * domain.  This driver is typically plumbed underneath the IP stack
 * or a software ethernet bridge.
 */

#include "xnb.h"

#include <sys/sunddi.h>
#include <sys/conf.h>
#include <sys/modctl.h>
#include <sys/strsubr.h>
#include <sys/dlpi.h>
#include <sys/pattr.h>
#include <sys/mac_provider.h>
#include <sys/mac_ether.h>
#include <xen/sys/xendev.h>
#include <sys/note.h>

/* Required driver entry points for GLDv3 */
static int  xnbu_m_start(void *);
static void xnbu_m_stop(void *);
static int  xnbu_m_set_mac_addr(void *, const uint8_t *);
static int  xnbu_m_set_multicast(void *, boolean_t, const uint8_t *);
static int  xnbu_m_set_promiscuous(void *, boolean_t);
static int  xnbu_m_stat(void *, uint_t, uint64_t *);
static boolean_t xnbu_m_getcapab(void *, mac_capab_t, void *);
static mblk_t   *xnbu_m_send(void *, mblk_t *);

typedef struct xnbu {
    mac_handle_t        u_mh;
    boolean_t       u_need_sched;
} xnbu_t;

static mac_callbacks_t xnbu_callbacks = {
    MC_GETCAPAB,
    xnbu_m_stat,
    xnbu_m_start,
    xnbu_m_stop,
    xnbu_m_set_promiscuous,
    xnbu_m_set_multicast,
    xnbu_m_set_mac_addr,
    xnbu_m_send,
    NULL,
    NULL,
    xnbu_m_getcapab
};

static void
xnbu_to_host(xnb_t *xnbp, mblk_t *mp)
{
    xnbu_t *xnbup = xnbp->xnb_flavour_data;
    boolean_t sched = B_FALSE;

    ASSERT(mp != NULL);

    mac_rx(xnbup->u_mh, NULL, mp);

    mutex_enter(&xnbp->xnb_rx_lock);

    /*
     * If a transmit attempt failed because we ran out of ring
     * space and there is now some space, re-enable the transmit
     * path.
     */
    if (xnbup->u_need_sched &&
        RING_HAS_UNCONSUMED_REQUESTS(&xnbp->xnb_rx_ring)) {
        sched = B_TRUE;
        xnbup->u_need_sched = B_FALSE;
    }

    mutex_exit(&xnbp->xnb_rx_lock);

    if (sched)
        mac_tx_update(xnbup->u_mh);
}

static mblk_t *
xnbu_cksum_from_peer(xnb_t *xnbp, mblk_t *mp, uint16_t flags)
{
    /*
     * Take a conservative approach - if the checksum is blank
     * then we fill it in.
     *
     * If the consumer of the packet is IP then we might actually
     * only need fill it in if the data is not validated, but how
     * do we know who might end up with the packet?
     */

    if ((flags & NETTXF_csum_blank) != 0) {
        /*
         * The checksum is blank.  We must fill it in here.
         */
        mp = xnb_process_cksum_flags(xnbp, mp, 0);

        /*
         * Because we calculated the checksum ourselves we
         * know that it must be good, so we assert this.
         */
        flags |= NETTXF_data_validated;
    }

    if ((flags & NETTXF_data_validated) != 0) {
        /*
         * The checksum is asserted valid.
         */
        mac_hcksum_set(mp, 0, 0, 0, 0, HCK_FULLCKSUM_OK);
    }

    return (mp);
}

static uint16_t
xnbu_cksum_to_peer(xnb_t *xnbp, mblk_t *mp)
{
    _NOTE(ARGUNUSED(xnbp));
    uint16_t r = 0;
    uint32_t pflags;

    mac_hcksum_get(mp, NULL, NULL, NULL, NULL, &pflags);

    /*
     * If the protocol stack has requested checksum
     * offload, inform the peer that we have not
     * calculated the checksum.
     */
    if ((pflags & HCK_FULLCKSUM) != 0)
        r |= NETRXF_csum_blank;

    return (r);
}

static boolean_t
xnbu_start_connect(xnb_t *xnbp)
{
    xnbu_t *xnbup = xnbp->xnb_flavour_data;

    mac_link_update(xnbup->u_mh, LINK_STATE_UP);
    /*
     * We are able to send packets now - bring them on.
     */
    mac_tx_update(xnbup->u_mh);

    return (B_TRUE);
}

static boolean_t
xnbu_peer_connected(xnb_t *xnbp)
{
    _NOTE(ARGUNUSED(xnbp));

    return (B_TRUE);
}

static void
xnbu_peer_disconnected(xnb_t *xnbp)
{
    xnbu_t *xnbup = xnbp->xnb_flavour_data;

    mac_link_update(xnbup->u_mh, LINK_STATE_DOWN);
}

/*ARGSUSED*/
static boolean_t
xnbu_hotplug_connected(xnb_t *xnbp)
{
    return (B_TRUE);
}

static mblk_t *
xnbu_m_send(void *arg, mblk_t *mp)
{
    xnb_t *xnbp = arg;
    xnbu_t *xnbup = xnbp->xnb_flavour_data;
    boolean_t sched = B_FALSE;

    mp = xnb_copy_to_peer(arg, mp);

    mutex_enter(&xnbp->xnb_rx_lock);
    /*
     * If we consumed all of the mblk_t's offered, perhaps we need
     * to indicate that we can accept more.  Otherwise we are full
     * and need to wait for space.
     */
    if (mp == NULL) {
        sched = xnbup->u_need_sched;
        xnbup->u_need_sched = B_FALSE;
    } else {
        xnbup->u_need_sched = B_TRUE;
    }
    mutex_exit(&xnbp->xnb_rx_lock);

    /*
     * If a previous transmit attempt failed because the ring
     * was full, try again now.
     */
    if (sched)
        mac_tx_update(xnbup->u_mh);

    return (mp);
}

/*
 *  xnbu_m_set_mac_addr() -- set the physical network address on the board
 */
/* ARGSUSED */
static int
xnbu_m_set_mac_addr(void *arg, const uint8_t *macaddr)
{
    xnb_t *xnbp = arg;
    xnbu_t *xnbup = xnbp->xnb_flavour_data;

    bcopy(macaddr, xnbp->xnb_mac_addr, ETHERADDRL);
    mac_unicst_update(xnbup->u_mh, xnbp->xnb_mac_addr);

    return (0);
}

/*
 *  xnbu_m_set_multicast() -- set (enable) or disable a multicast address
 */
/*ARGSUSED*/
static int
xnbu_m_set_multicast(void *arg, boolean_t add, const uint8_t *mca)
{
    /*
     * We always accept all packets from the peer, so nothing to
     * do for enable or disable.
     */
    return (0);
}


/*
 * xnbu_m_set_promiscuous() -- set or reset promiscuous mode on the board
 */
/* ARGSUSED */
static int
xnbu_m_set_promiscuous(void *arg, boolean_t on)
{
    /*
     * We always accept all packets from the peer, so nothing to
     * do for enable or disable.
     */
    return (0);
}

/*
 *  xnbu_m_start() -- start the board receiving and enable interrupts.
 */
/*ARGSUSED*/
static int
xnbu_m_start(void *arg)
{
    return (0);
}

/*
 * xnbu_m_stop() - disable hardware
 */
/*ARGSUSED*/
static void
xnbu_m_stop(void *arg)
{
}

static int
xnbu_m_stat(void *arg, uint_t stat, uint64_t *val)
{
    xnb_t *xnbp = arg;

    mutex_enter(&xnbp->xnb_tx_lock);
    mutex_enter(&xnbp->xnb_rx_lock);

#define map_stat(q, r)              \
    case (MAC_STAT_##q):            \
        *val = xnbp->xnb_stat_##r;  \
        break

    switch (stat) {

    map_stat(IPACKETS, opackets);
    map_stat(OPACKETS, ipackets);
    map_stat(RBYTES, obytes);
    map_stat(OBYTES, rbytes);

    default:
        mutex_exit(&xnbp->xnb_rx_lock);
        mutex_exit(&xnbp->xnb_tx_lock);

        return (ENOTSUP);
    }

#undef map_stat

    mutex_exit(&xnbp->xnb_rx_lock);
    mutex_exit(&xnbp->xnb_tx_lock);

    return (0);
}

static boolean_t
xnbu_m_getcapab(void *arg, mac_capab_t cap, void *cap_data)
{
    _NOTE(ARGUNUSED(arg));

    switch (cap) {
    case MAC_CAPAB_HCKSUM: {
        uint32_t *capab = cap_data;

        *capab = HCKSUM_INET_PARTIAL;
        break;
    }
    default:
        return (B_FALSE);
    }

    return (B_TRUE);
}

/*
 * All packets are passed to the peer, so adding and removing
 * multicast addresses is meaningless.
 */
static boolean_t
xnbu_mcast_add(xnb_t *xnbp, ether_addr_t *addr)
{
    _NOTE(ARGUNUSED(xnbp, addr));

    return (B_TRUE);
}

static boolean_t
xnbu_mcast_del(xnb_t *xnbp, ether_addr_t *addr)
{
    _NOTE(ARGUNUSED(xnbp, addr));

    return (B_TRUE);
}

static int
xnbu_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
{
    static xnb_flavour_t flavour = {
        xnbu_to_host, xnbu_peer_connected, xnbu_peer_disconnected,
        xnbu_hotplug_connected, xnbu_start_connect,
        xnbu_cksum_from_peer, xnbu_cksum_to_peer,
        xnbu_mcast_add, xnbu_mcast_del,
    };
    xnbu_t *xnbup;
    xnb_t *xnbp;
    mac_register_t *mr;
    int err;

    switch (cmd) {
    case DDI_ATTACH:
        break;
    case DDI_RESUME:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }

    xnbup = kmem_zalloc(sizeof (*xnbup), KM_SLEEP);

    if ((mr = mac_alloc(MAC_VERSION)) == NULL) {
        kmem_free(xnbup, sizeof (*xnbup));
        return (DDI_FAILURE);
    }

    if (xnb_attach(dip, &flavour, xnbup) != DDI_SUCCESS) {
        mac_free(mr);
        kmem_free(xnbup, sizeof (*xnbup));
        return (DDI_FAILURE);
    }

    xnbp = ddi_get_driver_private(dip);
    ASSERT(xnbp != NULL);

    mr->m_dip = dip;
    mr->m_driver = xnbp;

    /*
     *  Initialize pointers to device specific functions which will be
     *  used by the generic layer.
     */
    mr->m_type_ident = MAC_PLUGIN_IDENT_ETHER;
    mr->m_src_addr = xnbp->xnb_mac_addr;
    mr->m_callbacks = &xnbu_callbacks;
    mr->m_min_sdu = 0;
    mr->m_max_sdu = XNBMAXPKT;
    /*
     * xnbu is a virtual device, and it is not associated with any
     * physical device. Its margin size is determined by the maximum
     * packet size it can handle, which is PAGESIZE.
     */
    mr->m_margin = PAGESIZE - XNBMAXPKT - sizeof (struct ether_header);

    (void) memset(xnbp->xnb_mac_addr, 0xff, ETHERADDRL);
    xnbp->xnb_mac_addr[0] &= 0xfe;
    xnbup->u_need_sched = B_FALSE;

    /*
     * Register ourselves with the GLDv3 interface.
     */
    err = mac_register(mr, &xnbup->u_mh);
    mac_free(mr);
    if (err != 0) {
        xnb_detach(dip);
        kmem_free(xnbup, sizeof (*xnbup));
        return (DDI_FAILURE);
    }

    mac_link_update(xnbup->u_mh, LINK_STATE_DOWN);

    return (DDI_SUCCESS);
}

/*ARGSUSED*/
int
xnbu_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
{
    xnb_t *xnbp = ddi_get_driver_private(dip);
    xnbu_t *xnbup = xnbp->xnb_flavour_data;

    switch (cmd) {
    case DDI_DETACH:
        break;
    case DDI_SUSPEND:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }

    ASSERT(xnbp != NULL);
    ASSERT(xnbup != NULL);

    mutex_enter(&xnbp->xnb_tx_lock);
    mutex_enter(&xnbp->xnb_rx_lock);

    if (!xnbp->xnb_detachable || xnbp->xnb_connected ||
        (xnbp->xnb_tx_buf_count > 0)) {
        mutex_exit(&xnbp->xnb_rx_lock);
        mutex_exit(&xnbp->xnb_tx_lock);

        return (DDI_FAILURE);
    }

    mutex_exit(&xnbp->xnb_rx_lock);
    mutex_exit(&xnbp->xnb_tx_lock);

    /*
     * Attempt to unregister the mac.
     */
    if ((xnbup->u_mh != NULL) && (mac_unregister(xnbup->u_mh) != 0))
        return (DDI_FAILURE);
    kmem_free(xnbup, sizeof (*xnbup));

    xnb_detach(dip);

    return (DDI_SUCCESS);
}

DDI_DEFINE_STREAM_OPS(ops, nulldev, nulldev, xnbu_attach, xnbu_detach,
    nodev, NULL, D_MP, NULL, ddi_quiesce_not_supported);

static struct modldrv modldrv = {
    &mod_driverops, "xnbu driver", &ops
};

static struct modlinkage modlinkage = {
    MODREV_1, &modldrv, NULL
};

int
_init(void)
{
    int i;

    mac_init_ops(&ops, "xnbu");

    i = mod_install(&modlinkage);
    if (i != DDI_SUCCESS)
        mac_fini_ops(&ops);

    return (i);
}

int
_fini(void)
{
    int i;

    i = mod_remove(&modlinkage);
    if (i == DDI_SUCCESS)
        mac_fini_ops(&ops);

    return (i);
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&modlinkage, modinfop));
}