/*
 * Copyright (c) 2014 Nicira, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/in.h>
#include <linux/ip.h>
#include <linux/net.h>
#include <linux/rculist.h>
#include <linux/udp.h>
#include <linux/if_vlan.h>
#include <linux/module.h>

#include <net/geneve.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/udp.h>
#include <net/xfrm.h>

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

static struct vport_ops ovs_geneve_vport_ops;
/**
 * struct geneve_port - Keeps track of open UDP ports
 * @dst_port: destination port.
 */
struct geneve_port {
	u16 port_no;
};

static inline struct geneve_port *geneve_vport(const struct vport *vport)
{
	return vport_priv(vport);
}

static int geneve_get_options(const struct vport *vport,
			      struct sk_buff *skb)
{
	struct geneve_port *geneve_port = geneve_vport(vport);

	if (nla_put_u16(skb, OVS_TUNNEL_ATTR_DST_PORT, geneve_port->port_no))
		return -EMSGSIZE;
	return 0;
}

static int geneve_get_egress_tun_info(struct vport *vport, struct sk_buff *skb,
				      struct dp_upcall_info *upcall)
{
	struct geneve_port *geneve_port = geneve_vport(vport);
	struct net *net = ovs_dp_get_net(vport->dp);
	__be16 dport = htons(geneve_port->port_no);
	__be16 sport = udp_flow_src_port(net, skb, 1, USHRT_MAX, true);

	return ovs_tunnel_get_egress_info(upcall, ovs_dp_get_net(vport->dp),
					  skb, IPPROTO_UDP, sport, dport);
}

static struct vport *geneve_tnl_create(const struct vport_parms *parms)
{
	struct net *net = ovs_dp_get_net(parms->dp);
	struct nlattr *options = parms->options;
	struct geneve_port *geneve_port;
	struct net_device *dev;
	struct vport *vport;
	struct nlattr *a;
	u16 dst_port;
	int err;

	if (!options) {
		err = -EINVAL;
		goto error;
	}

	a = nla_find_nested(options, OVS_TUNNEL_ATTR_DST_PORT);
	if (a && nla_len(a) == sizeof(u16)) {
		dst_port = nla_get_u16(a);
	} else {
		/* Require destination port from userspace. */
		err = -EINVAL;
		goto error;
	}

	vport = ovs_vport_alloc(sizeof(struct geneve_port),
				&ovs_geneve_vport_ops, parms);
	if (IS_ERR(vport))
		return vport;

	geneve_port = geneve_vport(vport);
	geneve_port->port_no = dst_port;

	rtnl_lock();
	dev = geneve_dev_create_fb(net, parms->name, NET_NAME_USER, dst_port);
	if (IS_ERR(dev)) {
		rtnl_unlock();
		ovs_vport_free(vport);
		return ERR_CAST(dev);
	}

	dev_change_flags(dev, dev->flags | IFF_UP);
	rtnl_unlock();
	return vport;
error:
	return ERR_PTR(err);
}

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

	vport = geneve_tnl_create(parms);
	if (IS_ERR(vport))
		return vport;

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

static struct vport_ops ovs_geneve_vport_ops = {
	.type		= OVS_VPORT_TYPE_GENEVE,
	.create		= geneve_create,
	.destroy	= ovs_netdev_tunnel_destroy,
	.get_options	= geneve_get_options,
	.send		= dev_queue_xmit,
	.owner          = THIS_MODULE,
	.get_egress_tun_info	= geneve_get_egress_tun_info,
};

static int __init ovs_geneve_tnl_init(void)
{
	return ovs_vport_ops_register(&ovs_geneve_vport_ops);
}

static void __exit ovs_geneve_tnl_exit(void)
{
	ovs_vport_ops_unregister(&ovs_geneve_vport_ops);
}

module_init(ovs_geneve_tnl_init);
module_exit(ovs_geneve_tnl_exit);

MODULE_DESCRIPTION("OVS: Geneve swiching port");
MODULE_LICENSE("GPL");
MODULE_ALIAS("vport-type-5");