/*
 * 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 <linux/openvswitch.h>
#include <linux/export.h>

#include <net/ip_tunnels.h>
#include <net/rtnetlink.h>

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

static struct vport_ops ovs_netdev_vport_ops;

/* Must be called with rcu_read_lock. */
static void netdev_port_receive(struct sk_buff *skb)
{
        struct vport *vport;

        vport = ovs_netdev_get_vport(skb->dev);
        if (unlikely(!vport))
                goto error;

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

        /* 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).
         */
        skb = skb_share_check(skb, GFP_ATOMIC);
        if (unlikely(!skb))
                return;

        skb_push(skb, ETH_HLEN);
        skb_postpush_rcsum(skb, skb->data, ETH_HLEN);
        ovs_vport_receive(vport, skb, skb_tunnel_info(skb));
        return;
error:
        kfree_skb(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;

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

        netdev_port_receive(skb);
        return RX_HANDLER_CONSUMED;
}

static struct net_device *get_dpdev(const struct datapath *dp)
{
        struct vport *local;

        local = ovs_vport_ovsl(dp, OVSP_LOCAL);
        BUG_ON(!local);
        return local->dev;
}

struct vport *ovs_netdev_link(struct vport *vport, const char *name)
{
        int err;

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

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

        rtnl_lock();
        err = netdev_master_upper_dev_link(vport->dev,
                                           get_dpdev(vport->dp), NULL, NULL);
        if (err)
                goto error_unlock;

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

        dev_disable_lro(vport->dev);
        dev_set_promiscuity(vport->dev, 1);
        vport->dev->priv_flags |= IFF_OVS_DATAPATH;
        rtnl_unlock();

        return vport;

error_master_upper_dev_unlink:
        netdev_upper_dev_unlink(vport->dev, get_dpdev(vport->dp));
error_unlock:
        rtnl_unlock();
error_put:
        dev_put(vport->dev);
error_free_vport:
        ovs_vport_free(vport);
        return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(ovs_netdev_link);

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

        vport = ovs_vport_alloc(0, &ovs_netdev_vport_ops, parms);
        if (IS_ERR(vport))
                return vport;

        return ovs_netdev_link(vport, parms->name);
}

static void vport_netdev_free(struct rcu_head *rcu)
{
        struct vport *vport = container_of(rcu, struct vport, rcu);

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

void ovs_netdev_detach_dev(struct vport *vport)
{
        ASSERT_RTNL();
        vport->dev->priv_flags &= ~IFF_OVS_DATAPATH;
        netdev_rx_handler_unregister(vport->dev);
        netdev_upper_dev_unlink(vport->dev,
                                netdev_master_upper_dev_get(vport->dev));
        dev_set_promiscuity(vport->dev, -1);
}
EXPORT_SYMBOL_GPL(ovs_netdev_detach_dev);

static void netdev_destroy(struct vport *vport)
{
        rtnl_lock();
        if (vport->dev->priv_flags & IFF_OVS_DATAPATH)
                ovs_netdev_detach_dev(vport);
        rtnl_unlock();

        call_rcu(&vport->rcu, vport_netdev_free);
}

void ovs_netdev_tunnel_destroy(struct vport *vport)
{
        rtnl_lock();
        if (vport->dev->priv_flags & IFF_OVS_DATAPATH)
                ovs_netdev_detach_dev(vport);

        /* We can be invoked by both explicit vport deletion and
         * underlying netdev deregistration; delete the link only
         * if it's not already shutting down.
         */
        if (vport->dev->reg_state == NETREG_REGISTERED)
                rtnl_delete_link(vport->dev);
        dev_put(vport->dev);
        vport->dev = NULL;
        rtnl_unlock();

        call_rcu(&vport->rcu, vport_netdev_free);
}
EXPORT_SYMBOL_GPL(ovs_netdev_tunnel_destroy);

/* 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;
}

static struct vport_ops ovs_netdev_vport_ops = {
        .type           = OVS_VPORT_TYPE_NETDEV,
        .create         = netdev_create,
        .destroy        = netdev_destroy,
        .send           = dev_queue_xmit,
};

int __init ovs_netdev_init(void)
{
        return ovs_vport_ops_register(&ovs_netdev_vport_ops);
}

void ovs_netdev_exit(void)
{
        ovs_vport_ops_unregister(&ovs_netdev_vport_ops);
}