vport-netdev.c

Go to the documentation of this file.

/*
 * Copyright (c) 2007-2012 Nicira, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/if_arp.h>
#include <linux/if_bridge.h>
#include <linux/if_vlan.h>
#include <linux/kernel.h>
#include <linux/llc.h>
#include <linux/rtnetlink.h>
#include <linux/skbuff.h>

#include <net/llc.h>

#include "datapath.h"
#include "vport-internal_dev.h"
#include "vport-netdev.h"

/* Must be called with rcu_read_lock. */
static void netdev_port_receive(struct vport *vport, struct sk_buff *skb)
{
    if (unlikely(!vport)) {
        kfree_skb(skb);
        return;
    }

    /* Make our own copy of the packet.  Otherwise we will mangle the
     * packet for anyone who came before us (e.g. tcpdump via AF_PACKET).
     * (No one comes after us, since we tell handle_bridge() that we took
     * the packet.) */
    skb = skb_share_check(skb, GFP_ATOMIC);
    if (unlikely(!skb))
        return;

    skb_push(skb, ETH_HLEN);
    ovs_vport_receive(vport, skb);
}

/* Called with rcu_read_lock and bottom-halves disabled. */
static rx_handler_result_t netdev_frame_hook(struct sk_buff **pskb)
{
    struct sk_buff *skb = *pskb;
    struct vport *vport;

    if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
        return RX_HANDLER_PASS;

    vport = ovs_netdev_get_vport(skb->dev);

    netdev_port_receive(vport, skb);

    return RX_HANDLER_CONSUMED;
}

static struct vport *netdev_create(const struct vport_parms *parms)
{
    struct vport *vport;
    struct netdev_vport *netdev_vport;
    int err;

    vport = ovs_vport_alloc(sizeof(struct netdev_vport),
                &ovs_netdev_vport_ops, parms);
    if (IS_ERR(vport)) {
        err = PTR_ERR(vport);
        goto error;
    }

    netdev_vport = netdev_vport_priv(vport);

    netdev_vport->dev = dev_get_by_name(ovs_dp_get_net(vport->dp), parms->name);
    if (!netdev_vport->dev) {
        err = -ENODEV;
        goto error_free_vport;
    }

    if (netdev_vport->dev->flags & IFF_LOOPBACK ||
        netdev_vport->dev->type != ARPHRD_ETHER ||
        ovs_is_internal_dev(netdev_vport->dev)) {
        err = -EINVAL;
        goto error_put;
    }

    err = netdev_rx_handler_register(netdev_vport->dev, netdev_frame_hook,
                     vport);
    if (err)
        goto error_put;

    dev_set_promiscuity(netdev_vport->dev, 1);
    netdev_vport->dev->priv_flags |= IFF_OVS_DATAPATH;

    return vport;

error_put:
    dev_put(netdev_vport->dev);
error_free_vport:
    ovs_vport_free(vport);
error:
    return ERR_PTR(err);
}

static void netdev_destroy(struct vport *vport)
{
    struct netdev_vport *netdev_vport = netdev_vport_priv(vport);

    netdev_vport->dev->priv_flags &= ~IFF_OVS_DATAPATH;
    netdev_rx_handler_unregister(netdev_vport->dev);
    dev_set_promiscuity(netdev_vport->dev, -1);

    synchronize_rcu();

    dev_put(netdev_vport->dev);
    ovs_vport_free(vport);
}

const char *ovs_netdev_get_name(const struct vport *vport)
{
    const struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
    return netdev_vport->dev->name;
}

int ovs_netdev_get_ifindex(const struct vport *vport)
{
    const struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
    return netdev_vport->dev->ifindex;
}

static unsigned int packet_length(const struct sk_buff *skb)
{
    unsigned int length = skb->len - ETH_HLEN;

    if (skb->protocol == htons(ETH_P_8021Q))
        length -= VLAN_HLEN;

    return length;
}

static int netdev_send(struct vport *vport, struct sk_buff *skb)
{
    struct netdev_vport *netdev_vport = netdev_vport_priv(vport);
    int mtu = netdev_vport->dev->mtu;
    int len;

    if (unlikely(packet_length(skb) > mtu && !skb_is_gso(skb))) {
        net_warn_ratelimited("%s: dropped over-mtu packet: %d > %d\n",
                     netdev_vport->dev->name,
                     packet_length(skb), mtu);
        goto error;
    }

    if (unlikely(skb_warn_if_lro(skb)))
        goto error;

    skb->dev = netdev_vport->dev;
    len = skb->len;
    dev_queue_xmit(skb);

    return len;

error:
    kfree_skb(skb);
    ovs_vport_record_error(vport, VPORT_E_TX_DROPPED);
    return 0;
}

/* Returns null if this device is not attached to a datapath. */
struct vport *ovs_netdev_get_vport(struct net_device *dev)
{
    if (likely(dev->priv_flags & IFF_OVS_DATAPATH))
        return (struct vport *)
            rcu_dereference_rtnl(dev->rx_handler_data);
    else
        return NULL;
}

const struct vport_ops ovs_netdev_vport_ops = {
    .type       = OVS_VPORT_TYPE_NETDEV,
    .create     = netdev_create,
    .destroy    = netdev_destroy,
    .get_name   = ovs_netdev_get_name,
    .get_ifindex    = ovs_netdev_get_ifindex,
    .send       = netdev_send,
};