/*
 * 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));
}