ipoib_multicast.c

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/*
 * Copyright (c) 2004, 2005 Topspin Communications.  All rights reserved.
 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
 * Copyright (c) 2004 Voltaire, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/moduleparam.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <linux/igmp.h>
#include <linux/inetdevice.h>
#include <linux/delay.h>
#include <linux/completion.h>
#include <linux/slab.h>

#include <net/dst.h>

#include "ipoib.h"

#ifdef CONFIG_INFINIBAND_IPOIB_DEBUG
static int mcast_debug_level;

module_param(mcast_debug_level, int, 0644);
MODULE_PARM_DESC(mcast_debug_level,
         "Enable multicast debug tracing if > 0");
#endif

static DEFINE_MUTEX(mcast_mutex);

struct ipoib_mcast_iter {
    struct net_device *dev;
    union ib_gid       mgid;
    unsigned long      created;
    unsigned int       queuelen;
    unsigned int       complete;
    unsigned int       send_only;
};

static void ipoib_mcast_free(struct ipoib_mcast *mcast)
{
    struct net_device *dev = mcast->dev;
    int tx_dropped = 0;

    ipoib_dbg_mcast(netdev_priv(dev), "deleting multicast group %pI6\n",
            mcast->mcmember.mgid.raw);

    /* remove all neigh connected to this mcast */
    ipoib_del_neighs_by_gid(dev, mcast->mcmember.mgid.raw);

    if (mcast->ah)
        ipoib_put_ah(mcast->ah);

    while (!skb_queue_empty(&mcast->pkt_queue)) {
        ++tx_dropped;
        dev_kfree_skb_any(skb_dequeue(&mcast->pkt_queue));
    }

    netif_tx_lock_bh(dev);
    dev->stats.tx_dropped += tx_dropped;
    netif_tx_unlock_bh(dev);

    kfree(mcast);
}

static struct ipoib_mcast *ipoib_mcast_alloc(struct net_device *dev,
                         int can_sleep)
{
    struct ipoib_mcast *mcast;

    mcast = kzalloc(sizeof *mcast, can_sleep ? GFP_KERNEL : GFP_ATOMIC);
    if (!mcast)
        return NULL;

    mcast->dev = dev;
    mcast->created = jiffies;
    mcast->backoff = 1;

    INIT_LIST_HEAD(&mcast->list);
    INIT_LIST_HEAD(&mcast->neigh_list);
    skb_queue_head_init(&mcast->pkt_queue);

    return mcast;
}

static struct ipoib_mcast *__ipoib_mcast_find(struct net_device *dev, void *mgid)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct rb_node *n = priv->multicast_tree.rb_node;

    while (n) {
        struct ipoib_mcast *mcast;
        int ret;

        mcast = rb_entry(n, struct ipoib_mcast, rb_node);

        ret = memcmp(mgid, mcast->mcmember.mgid.raw,
                 sizeof (union ib_gid));
        if (ret < 0)
            n = n->rb_left;
        else if (ret > 0)
            n = n->rb_right;
        else
            return mcast;
    }

    return NULL;
}

static int __ipoib_mcast_add(struct net_device *dev, struct ipoib_mcast *mcast)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct rb_node **n = &priv->multicast_tree.rb_node, *pn = NULL;

    while (*n) {
        struct ipoib_mcast *tmcast;
        int ret;

        pn = *n;
        tmcast = rb_entry(pn, struct ipoib_mcast, rb_node);

        ret = memcmp(mcast->mcmember.mgid.raw, tmcast->mcmember.mgid.raw,
                 sizeof (union ib_gid));
        if (ret < 0)
            n = &pn->rb_left;
        else if (ret > 0)
            n = &pn->rb_right;
        else
            return -EEXIST;
    }

    rb_link_node(&mcast->rb_node, pn, n);
    rb_insert_color(&mcast->rb_node, &priv->multicast_tree);

    return 0;
}

static int ipoib_mcast_join_finish(struct ipoib_mcast *mcast,
                   struct ib_sa_mcmember_rec *mcmember)
{
    struct net_device *dev = mcast->dev;
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct ipoib_ah *ah;
    int ret;
    int set_qkey = 0;

    mcast->mcmember = *mcmember;

    /* Set the multicast MTU and cached Q_Key before we attach if it's
     * the broadcast group.
     */
    if (!memcmp(mcast->mcmember.mgid.raw, priv->dev->broadcast + 4,
            sizeof (union ib_gid))) {
        spin_lock_irq(&priv->lock);
        if (!priv->broadcast) {
            spin_unlock_irq(&priv->lock);
            return -EAGAIN;
        }
        priv->mcast_mtu = IPOIB_UD_MTU(ib_mtu_enum_to_int(priv->broadcast->mcmember.mtu));
        priv->qkey = be32_to_cpu(priv->broadcast->mcmember.qkey);
        spin_unlock_irq(&priv->lock);
        priv->tx_wr.wr.ud.remote_qkey = priv->qkey;
        set_qkey = 1;

        if (!ipoib_cm_admin_enabled(dev)) {
            rtnl_lock();
            dev_set_mtu(dev, min(priv->mcast_mtu, priv->admin_mtu));
            rtnl_unlock();
        }
    }

    if (!test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
        if (test_and_set_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags)) {
            ipoib_warn(priv, "multicast group %pI6 already attached\n",
                   mcast->mcmember.mgid.raw);

            return 0;
        }

        ret = ipoib_mcast_attach(dev, be16_to_cpu(mcast->mcmember.mlid),
                     &mcast->mcmember.mgid, set_qkey);
        if (ret < 0) {
            ipoib_warn(priv, "couldn't attach QP to multicast group %pI6\n",
                   mcast->mcmember.mgid.raw);

            clear_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags);
            return ret;
        }
    }

    {
        struct ib_ah_attr av = {
            .dlid          = be16_to_cpu(mcast->mcmember.mlid),
            .port_num      = priv->port,
            .sl        = mcast->mcmember.sl,
            .ah_flags      = IB_AH_GRH,
            .static_rate   = mcast->mcmember.rate,
            .grh           = {
                .flow_label    = be32_to_cpu(mcast->mcmember.flow_label),
                .hop_limit     = mcast->mcmember.hop_limit,
                .sgid_index    = 0,
                .traffic_class = mcast->mcmember.traffic_class
            }
        };
        av.grh.dgid = mcast->mcmember.mgid;

        ah = ipoib_create_ah(dev, priv->pd, &av);
        if (IS_ERR(ah)) {
            ipoib_warn(priv, "ib_address_create failed %ld\n",
                -PTR_ERR(ah));
            /* use original error */
            return PTR_ERR(ah);
        } else {
            spin_lock_irq(&priv->lock);
            mcast->ah = ah;
            spin_unlock_irq(&priv->lock);

            ipoib_dbg_mcast(priv, "MGID %pI6 AV %p, LID 0x%04x, SL %d\n",
                    mcast->mcmember.mgid.raw,
                    mcast->ah->ah,
                    be16_to_cpu(mcast->mcmember.mlid),
                    mcast->mcmember.sl);
        }
    }

    /* actually send any queued packets */
    netif_tx_lock_bh(dev);
    while (!skb_queue_empty(&mcast->pkt_queue)) {
        struct sk_buff *skb = skb_dequeue(&mcast->pkt_queue);

        netif_tx_unlock_bh(dev);

        skb->dev = dev;
        if (dev_queue_xmit(skb))
            ipoib_warn(priv, "dev_queue_xmit failed to requeue packet\n");

        netif_tx_lock_bh(dev);
    }
    netif_tx_unlock_bh(dev);

    return 0;
}

static int
ipoib_mcast_sendonly_join_complete(int status,
                   struct ib_sa_multicast *multicast)
{
    struct ipoib_mcast *mcast = multicast->context;
    struct net_device *dev = mcast->dev;

    /* We trap for port events ourselves. */
    if (status == -ENETRESET)
        return 0;

    if (!status)
        status = ipoib_mcast_join_finish(mcast, &multicast->rec);

    if (status) {
        if (mcast->logcount++ < 20)
            ipoib_dbg_mcast(netdev_priv(dev), "multicast join failed for %pI6, status %d\n",
                    mcast->mcmember.mgid.raw, status);

        /* Flush out any queued packets */
        netif_tx_lock_bh(dev);
        while (!skb_queue_empty(&mcast->pkt_queue)) {
            ++dev->stats.tx_dropped;
            dev_kfree_skb_any(skb_dequeue(&mcast->pkt_queue));
        }
        netif_tx_unlock_bh(dev);

        /* Clear the busy flag so we try again */
        status = test_and_clear_bit(IPOIB_MCAST_FLAG_BUSY,
                        &mcast->flags);
    }
    return status;
}

static int ipoib_mcast_sendonly_join(struct ipoib_mcast *mcast)
{
    struct net_device *dev = mcast->dev;
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct ib_sa_mcmember_rec rec = {
#if 0               /* Some SMs don't support send-only yet */
        .join_state = 4
#else
        .join_state = 1
#endif
    };
    int ret = 0;

    if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags)) {
        ipoib_dbg_mcast(priv, "device shutting down, no multicast joins\n");
        return -ENODEV;
    }

    if (test_and_set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags)) {
        ipoib_dbg_mcast(priv, "multicast entry busy, skipping\n");
        return -EBUSY;
    }

    rec.mgid     = mcast->mcmember.mgid;
    rec.port_gid = priv->local_gid;
    rec.pkey     = cpu_to_be16(priv->pkey);

    mcast->mc = ib_sa_join_multicast(&ipoib_sa_client, priv->ca,
                     priv->port, &rec,
                     IB_SA_MCMEMBER_REC_MGID    |
                     IB_SA_MCMEMBER_REC_PORT_GID    |
                     IB_SA_MCMEMBER_REC_PKEY    |
                     IB_SA_MCMEMBER_REC_JOIN_STATE,
                     GFP_ATOMIC,
                     ipoib_mcast_sendonly_join_complete,
                     mcast);
    if (IS_ERR(mcast->mc)) {
        ret = PTR_ERR(mcast->mc);
        clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
        ipoib_warn(priv, "ib_sa_join_multicast failed (ret = %d)\n",
               ret);
    } else {
        ipoib_dbg_mcast(priv, "no multicast record for %pI6, starting join\n",
                mcast->mcmember.mgid.raw);
    }

    return ret;
}

void ipoib_mcast_carrier_on_task(struct work_struct *work)
{
    struct ipoib_dev_priv *priv = container_of(work, struct ipoib_dev_priv,
                           carrier_on_task);
    struct ib_port_attr attr;

    /*
     * Take rtnl_lock to avoid racing with ipoib_stop() and
     * turning the carrier back on while a device is being
     * removed.
     */
    if (ib_query_port(priv->ca, priv->port, &attr) ||
        attr.state != IB_PORT_ACTIVE) {
        ipoib_dbg(priv, "Keeping carrier off until IB port is active\n");
        return;
    }

    rtnl_lock();
    netif_carrier_on(priv->dev);
    rtnl_unlock();
}

static int ipoib_mcast_join_complete(int status,
                     struct ib_sa_multicast *multicast)
{
    struct ipoib_mcast *mcast = multicast->context;
    struct net_device *dev = mcast->dev;
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    ipoib_dbg_mcast(priv, "join completion for %pI6 (status %d)\n",
            mcast->mcmember.mgid.raw, status);

    /* We trap for port events ourselves. */
    if (status == -ENETRESET)
        return 0;

    if (!status)
        status = ipoib_mcast_join_finish(mcast, &multicast->rec);

    if (!status) {
        mcast->backoff = 1;
        mutex_lock(&mcast_mutex);
        if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
            queue_delayed_work(ipoib_workqueue,
                       &priv->mcast_task, 0);
        mutex_unlock(&mcast_mutex);

        /*
         * Defer carrier on work to ipoib_workqueue to avoid a
         * deadlock on rtnl_lock here.
         */
        if (mcast == priv->broadcast)
            queue_work(ipoib_workqueue, &priv->carrier_on_task);

        return 0;
    }

    if (mcast->logcount++ < 20) {
        if (status == -ETIMEDOUT || status == -EAGAIN) {
            ipoib_dbg_mcast(priv, "multicast join failed for %pI6, status %d\n",
                    mcast->mcmember.mgid.raw, status);
        } else {
            ipoib_warn(priv, "multicast join failed for %pI6, status %d\n",
                   mcast->mcmember.mgid.raw, status);
        }
    }

    mcast->backoff *= 2;
    if (mcast->backoff > IPOIB_MAX_BACKOFF_SECONDS)
        mcast->backoff = IPOIB_MAX_BACKOFF_SECONDS;

    /* Clear the busy flag so we try again */
    status = test_and_clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);

    mutex_lock(&mcast_mutex);
    spin_lock_irq(&priv->lock);
    if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
        queue_delayed_work(ipoib_workqueue, &priv->mcast_task,
                   mcast->backoff * HZ);
    spin_unlock_irq(&priv->lock);
    mutex_unlock(&mcast_mutex);

    return status;
}

static void ipoib_mcast_join(struct net_device *dev, struct ipoib_mcast *mcast,
                 int create)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct ib_sa_mcmember_rec rec = {
        .join_state = 1
    };
    ib_sa_comp_mask comp_mask;
    int ret = 0;

    ipoib_dbg_mcast(priv, "joining MGID %pI6\n", mcast->mcmember.mgid.raw);

    rec.mgid     = mcast->mcmember.mgid;
    rec.port_gid = priv->local_gid;
    rec.pkey     = cpu_to_be16(priv->pkey);

    comp_mask =
        IB_SA_MCMEMBER_REC_MGID     |
        IB_SA_MCMEMBER_REC_PORT_GID |
        IB_SA_MCMEMBER_REC_PKEY     |
        IB_SA_MCMEMBER_REC_JOIN_STATE;

    if (create) {
        comp_mask |=
            IB_SA_MCMEMBER_REC_QKEY         |
            IB_SA_MCMEMBER_REC_MTU_SELECTOR     |
            IB_SA_MCMEMBER_REC_MTU          |
            IB_SA_MCMEMBER_REC_TRAFFIC_CLASS    |
            IB_SA_MCMEMBER_REC_RATE_SELECTOR    |
            IB_SA_MCMEMBER_REC_RATE         |
            IB_SA_MCMEMBER_REC_SL           |
            IB_SA_MCMEMBER_REC_FLOW_LABEL       |
            IB_SA_MCMEMBER_REC_HOP_LIMIT;

        rec.qkey      = priv->broadcast->mcmember.qkey;
        rec.mtu_selector  = IB_SA_EQ;
        rec.mtu       = priv->broadcast->mcmember.mtu;
        rec.traffic_class = priv->broadcast->mcmember.traffic_class;
        rec.rate_selector = IB_SA_EQ;
        rec.rate      = priv->broadcast->mcmember.rate;
        rec.sl        = priv->broadcast->mcmember.sl;
        rec.flow_label    = priv->broadcast->mcmember.flow_label;
        rec.hop_limit     = priv->broadcast->mcmember.hop_limit;
    }

    set_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
    mcast->mc = ib_sa_join_multicast(&ipoib_sa_client, priv->ca, priv->port,
                     &rec, comp_mask, GFP_KERNEL,
                     ipoib_mcast_join_complete, mcast);
    if (IS_ERR(mcast->mc)) {
        clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags);
        ret = PTR_ERR(mcast->mc);
        ipoib_warn(priv, "ib_sa_join_multicast failed, status %d\n", ret);

        mcast->backoff *= 2;
        if (mcast->backoff > IPOIB_MAX_BACKOFF_SECONDS)
            mcast->backoff = IPOIB_MAX_BACKOFF_SECONDS;

        mutex_lock(&mcast_mutex);
        if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
            queue_delayed_work(ipoib_workqueue,
                       &priv->mcast_task,
                       mcast->backoff * HZ);
        mutex_unlock(&mcast_mutex);
    }
}

void ipoib_mcast_join_task(struct work_struct *work)
{
    struct ipoib_dev_priv *priv =
        container_of(work, struct ipoib_dev_priv, mcast_task.work);
    struct net_device *dev = priv->dev;

    if (!test_bit(IPOIB_MCAST_RUN, &priv->flags))
        return;

    if (ib_query_gid(priv->ca, priv->port, 0, &priv->local_gid))
        ipoib_warn(priv, "ib_query_gid() failed\n");
    else
        memcpy(priv->dev->dev_addr + 4, priv->local_gid.raw, sizeof (union ib_gid));

    {
        struct ib_port_attr attr;

        if (!ib_query_port(priv->ca, priv->port, &attr))
            priv->local_lid = attr.lid;
        else
            ipoib_warn(priv, "ib_query_port failed\n");
    }

    if (!priv->broadcast) {
        struct ipoib_mcast *broadcast;

        if (!test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
            return;

        broadcast = ipoib_mcast_alloc(dev, 1);
        if (!broadcast) {
            ipoib_warn(priv, "failed to allocate broadcast group\n");
            mutex_lock(&mcast_mutex);
            if (test_bit(IPOIB_MCAST_RUN, &priv->flags))
                queue_delayed_work(ipoib_workqueue,
                           &priv->mcast_task, HZ);
            mutex_unlock(&mcast_mutex);
            return;
        }

        spin_lock_irq(&priv->lock);
        memcpy(broadcast->mcmember.mgid.raw, priv->dev->broadcast + 4,
               sizeof (union ib_gid));
        priv->broadcast = broadcast;

        __ipoib_mcast_add(dev, priv->broadcast);
        spin_unlock_irq(&priv->lock);
    }

    if (!test_bit(IPOIB_MCAST_FLAG_ATTACHED, &priv->broadcast->flags)) {
        if (!test_bit(IPOIB_MCAST_FLAG_BUSY, &priv->broadcast->flags))
            ipoib_mcast_join(dev, priv->broadcast, 0);
        return;
    }

    while (1) {
        struct ipoib_mcast *mcast = NULL;

        spin_lock_irq(&priv->lock);
        list_for_each_entry(mcast, &priv->multicast_list, list) {
            if (!test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)
                && !test_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags)
                && !test_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags)) {
                /* Found the next unjoined group */
                break;
            }
        }
        spin_unlock_irq(&priv->lock);

        if (&mcast->list == &priv->multicast_list) {
            /* All done */
            break;
        }

        ipoib_mcast_join(dev, mcast, 1);
        return;
    }

    ipoib_dbg_mcast(priv, "successfully joined all multicast groups\n");

    clear_bit(IPOIB_MCAST_RUN, &priv->flags);
}

int ipoib_mcast_start_thread(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    ipoib_dbg_mcast(priv, "starting multicast thread\n");

    mutex_lock(&mcast_mutex);
    if (!test_and_set_bit(IPOIB_MCAST_RUN, &priv->flags))
        queue_delayed_work(ipoib_workqueue, &priv->mcast_task, 0);
    mutex_unlock(&mcast_mutex);

    return 0;
}

int ipoib_mcast_stop_thread(struct net_device *dev, int flush)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);

    ipoib_dbg_mcast(priv, "stopping multicast thread\n");

    mutex_lock(&mcast_mutex);
    clear_bit(IPOIB_MCAST_RUN, &priv->flags);
    cancel_delayed_work(&priv->mcast_task);
    mutex_unlock(&mcast_mutex);

    if (flush)
        flush_workqueue(ipoib_workqueue);

    return 0;
}

static int ipoib_mcast_leave(struct net_device *dev, struct ipoib_mcast *mcast)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    int ret = 0;

    if (test_and_clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))
        ib_sa_free_multicast(mcast->mc);

    if (test_and_clear_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags)) {
        ipoib_dbg_mcast(priv, "leaving MGID %pI6\n",
                mcast->mcmember.mgid.raw);

        /* Remove ourselves from the multicast group */
        ret = ib_detach_mcast(priv->qp, &mcast->mcmember.mgid,
                      be16_to_cpu(mcast->mcmember.mlid));
        if (ret)
            ipoib_warn(priv, "ib_detach_mcast failed (result = %d)\n", ret);
    }

    return 0;
}

void ipoib_mcast_send(struct net_device *dev, u8 *daddr, struct sk_buff *skb)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    struct ipoib_mcast *mcast;
    unsigned long flags;
    void *mgid = daddr + 4;

    spin_lock_irqsave(&priv->lock, flags);

    if (!test_bit(IPOIB_FLAG_OPER_UP, &priv->flags)     ||
        !priv->broadcast                    ||
        !test_bit(IPOIB_MCAST_FLAG_ATTACHED, &priv->broadcast->flags)) {
        ++dev->stats.tx_dropped;
        dev_kfree_skb_any(skb);
        goto unlock;
    }

    mcast = __ipoib_mcast_find(dev, mgid);
    if (!mcast) {
        /* Let's create a new send only group now */
        ipoib_dbg_mcast(priv, "setting up send only multicast group for %pI6\n",
                mgid);

        mcast = ipoib_mcast_alloc(dev, 0);
        if (!mcast) {
            ipoib_warn(priv, "unable to allocate memory for "
                   "multicast structure\n");
            ++dev->stats.tx_dropped;
            dev_kfree_skb_any(skb);
            goto out;
        }

        set_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags);
        memcpy(mcast->mcmember.mgid.raw, mgid, sizeof (union ib_gid));
        __ipoib_mcast_add(dev, mcast);
        list_add_tail(&mcast->list, &priv->multicast_list);
    }

    if (!mcast->ah) {
        if (skb_queue_len(&mcast->pkt_queue) < IPOIB_MAX_MCAST_QUEUE)
            skb_queue_tail(&mcast->pkt_queue, skb);
        else {
            ++dev->stats.tx_dropped;
            dev_kfree_skb_any(skb);
        }

        if (test_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))
            ipoib_dbg_mcast(priv, "no address vector, "
                    "but multicast join already started\n");
        else if (test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags))
            ipoib_mcast_sendonly_join(mcast);

        /*
         * If lookup completes between here and out:, don't
         * want to send packet twice.
         */
        mcast = NULL;
    }

out:
    if (mcast && mcast->ah) {
        struct ipoib_neigh *neigh;

        spin_unlock_irqrestore(&priv->lock, flags);
        neigh = ipoib_neigh_get(dev, daddr);
        spin_lock_irqsave(&priv->lock, flags);
        if (!neigh) {
            neigh = ipoib_neigh_alloc(daddr, dev);
            if (neigh) {
                kref_get(&mcast->ah->ref);
                neigh->ah   = mcast->ah;
                list_add_tail(&neigh->list, &mcast->neigh_list);
            }
        }
        spin_unlock_irqrestore(&priv->lock, flags);
        ipoib_send(dev, skb, mcast->ah, IB_MULTICAST_QPN);
        if (neigh)
            ipoib_neigh_put(neigh);
        return;
    }

unlock:
    spin_unlock_irqrestore(&priv->lock, flags);
}

void ipoib_mcast_dev_flush(struct net_device *dev)
{
    struct ipoib_dev_priv *priv = netdev_priv(dev);
    LIST_HEAD(remove_list);
    struct ipoib_mcast *mcast, *tmcast;
    unsigned long flags;

    ipoib_dbg_mcast(priv, "flushing multicast list\n");

    spin_lock_irqsave(&priv->lock, flags);

    list_for_each_entry_safe(mcast, tmcast, &priv->multicast_list, list) {
        list_del(&mcast->list);
        rb_erase(&mcast->rb_node, &priv->multicast_tree);
        list_add_tail(&mcast->list, &remove_list);
    }

    if (priv->broadcast) {
        rb_erase(&priv->broadcast->rb_node, &priv->multicast_tree);
        list_add_tail(&priv->broadcast->list, &remove_list);
        priv->broadcast = NULL;
    }

    spin_unlock_irqrestore(&priv->lock, flags);

    list_for_each_entry_safe(mcast, tmcast, &remove_list, list) {
        ipoib_mcast_leave(dev, mcast);
        ipoib_mcast_free(mcast);
    }
}

static int ipoib_mcast_addr_is_valid(const u8 *addr, const u8 *broadcast)
{
    /* reserved QPN, prefix, scope */
    if (memcmp(addr, broadcast, 6))
        return 0;
    /* signature lower, pkey */
    if (memcmp(addr + 7, broadcast + 7, 3))
        return 0;
    return 1;
}

void ipoib_mcast_restart_task(struct work_struct *work)
{
    struct ipoib_dev_priv *priv =
        container_of(work, struct ipoib_dev_priv, restart_task);
    struct net_device *dev = priv->dev;
    struct netdev_hw_addr *ha;
    struct ipoib_mcast *mcast, *tmcast;
    LIST_HEAD(remove_list);
    unsigned long flags;
    struct ib_sa_mcmember_rec rec;

    ipoib_dbg_mcast(priv, "restarting multicast task\n");

    ipoib_mcast_stop_thread(dev, 0);

    local_irq_save(flags);
    netif_addr_lock(dev);
    spin_lock(&priv->lock);

    /*
     * Unfortunately, the networking core only gives us a list of all of
     * the multicast hardware addresses. We need to figure out which ones
     * are new and which ones have been removed
     */

    /* Clear out the found flag */
    list_for_each_entry(mcast, &priv->multicast_list, list)
        clear_bit(IPOIB_MCAST_FLAG_FOUND, &mcast->flags);

    /* Mark all of the entries that are found or don't exist */
    netdev_for_each_mc_addr(ha, dev) {
        union ib_gid mgid;

        if (!ipoib_mcast_addr_is_valid(ha->addr, dev->broadcast))
            continue;

        memcpy(mgid.raw, ha->addr + 4, sizeof mgid);

        mcast = __ipoib_mcast_find(dev, &mgid);
        if (!mcast || test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
            struct ipoib_mcast *nmcast;

            /* ignore group which is directly joined by userspace */
            if (test_bit(IPOIB_FLAG_UMCAST, &priv->flags) &&
                !ib_sa_get_mcmember_rec(priv->ca, priv->port, &mgid, &rec)) {
                ipoib_dbg_mcast(priv, "ignoring multicast entry for mgid %pI6\n",
                        mgid.raw);
                continue;
            }

            /* Not found or send-only group, let's add a new entry */
            ipoib_dbg_mcast(priv, "adding multicast entry for mgid %pI6\n",
                    mgid.raw);

            nmcast = ipoib_mcast_alloc(dev, 0);
            if (!nmcast) {
                ipoib_warn(priv, "unable to allocate memory for multicast structure\n");
                continue;
            }

            set_bit(IPOIB_MCAST_FLAG_FOUND, &nmcast->flags);

            nmcast->mcmember.mgid = mgid;

            if (mcast) {
                /* Destroy the send only entry */
                list_move_tail(&mcast->list, &remove_list);

                rb_replace_node(&mcast->rb_node,
                        &nmcast->rb_node,
                        &priv->multicast_tree);
            } else
                __ipoib_mcast_add(dev, nmcast);

            list_add_tail(&nmcast->list, &priv->multicast_list);
        }

        if (mcast)
            set_bit(IPOIB_MCAST_FLAG_FOUND, &mcast->flags);
    }

    /* Remove all of the entries don't exist anymore */
    list_for_each_entry_safe(mcast, tmcast, &priv->multicast_list, list) {
        if (!test_bit(IPOIB_MCAST_FLAG_FOUND, &mcast->flags) &&
            !test_bit(IPOIB_MCAST_FLAG_SENDONLY, &mcast->flags)) {
            ipoib_dbg_mcast(priv, "deleting multicast group %pI6\n",
                    mcast->mcmember.mgid.raw);

            rb_erase(&mcast->rb_node, &priv->multicast_tree);

            /* Move to the remove list */
            list_move_tail(&mcast->list, &remove_list);
        }
    }

    spin_unlock(&priv->lock);
    netif_addr_unlock(dev);
    local_irq_restore(flags);

    /* We have to cancel outside of the spinlock */
    list_for_each_entry_safe(mcast, tmcast, &remove_list, list) {
        ipoib_mcast_leave(mcast->dev, mcast);
        ipoib_mcast_free(mcast);
    }

    if (test_bit(IPOIB_FLAG_ADMIN_UP, &priv->flags))
        ipoib_mcast_start_thread(dev);
}

#ifdef CONFIG_INFINIBAND_IPOIB_DEBUG

struct ipoib_mcast_iter *ipoib_mcast_iter_init(struct net_device *dev)
{
    struct ipoib_mcast_iter *iter;

    iter = kmalloc(sizeof *iter, GFP_KERNEL);
    if (!iter)
        return NULL;

    iter->dev = dev;
    memset(iter->mgid.raw, 0, 16);

    if (ipoib_mcast_iter_next(iter)) {
        kfree(iter);
        return NULL;
    }

    return iter;
}

int ipoib_mcast_iter_next(struct ipoib_mcast_iter *iter)
{
    struct ipoib_dev_priv *priv = netdev_priv(iter->dev);
    struct rb_node *n;
    struct ipoib_mcast *mcast;
    int ret = 1;

    spin_lock_irq(&priv->lock);

    n = rb_first(&priv->multicast_tree);

    while (n) {
        mcast = rb_entry(n, struct ipoib_mcast, rb_node);

        if (memcmp(iter->mgid.raw, mcast->mcmember.mgid.raw,
               sizeof (union ib_gid)) < 0) {
            iter->mgid      = mcast->mcmember.mgid;
            iter->created   = mcast->created;
            iter->queuelen  = skb_queue_len(&mcast->pkt_queue);
            iter->complete  = !!mcast->ah;
            iter->send_only = !!(mcast->flags & (1 << IPOIB_MCAST_FLAG_SENDONLY));

            ret = 0;

            break;
        }

        n = rb_next(n);
    }

    spin_unlock_irq(&priv->lock);

    return ret;
}

void ipoib_mcast_iter_read(struct ipoib_mcast_iter *iter,
               union ib_gid *mgid,
               unsigned long *created,
               unsigned int *queuelen,
               unsigned int *complete,
               unsigned int *send_only)
{
    *mgid      = iter->mgid;
    *created   = iter->created;
    *queuelen  = iter->queuelen;
    *complete  = iter->complete;
    *send_only = iter->send_only;
}

#endif /* CONFIG_INFINIBAND_IPOIB_DEBUG */