/*
 * Copyright (C) 2017 Netronome Systems, Inc.
 *
 * This software is licensed under the GNU General License Version 2,
 * June 1991 as shown in the file COPYING in the top-level directory of this
 * source tree.
 *
 * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
 * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
 * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
 * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
 */

#include <linux/etherdevice.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <net/netlink.h>
#include <net/rtnetlink.h>

#include "netdevsim.h"

static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct netdevsim *ns = netdev_priv(dev);

	u64_stats_update_begin(&ns->syncp);
	ns->tx_packets++;
	ns->tx_bytes += skb->len;
	u64_stats_update_end(&ns->syncp);

	dev_kfree_skb(skb);

	return NETDEV_TX_OK;
}

static void nsim_set_rx_mode(struct net_device *dev)
{
}

static void
nsim_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
{
	struct netdevsim *ns = netdev_priv(dev);
	unsigned int start;

	do {
		start = u64_stats_fetch_begin(&ns->syncp);
		stats->tx_bytes = ns->tx_bytes;
		stats->tx_packets = ns->tx_packets;
	} while (u64_stats_fetch_retry(&ns->syncp, start));
}

static const struct net_device_ops nsim_netdev_ops = {
	.ndo_start_xmit		= nsim_start_xmit,
	.ndo_set_rx_mode	= nsim_set_rx_mode,
	.ndo_set_mac_address	= eth_mac_addr,
	.ndo_validate_addr	= eth_validate_addr,
	.ndo_get_stats64	= nsim_get_stats64,
};

static void nsim_setup(struct net_device *dev)
{
	ether_setup(dev);
	eth_hw_addr_random(dev);

	dev->netdev_ops = &nsim_netdev_ops;
	dev->needs_free_netdev = true;

	dev->tx_queue_len = 0;
	dev->flags |= IFF_NOARP;
	dev->flags &= ~IFF_MULTICAST;
	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE |
			   IFF_NO_QUEUE;
	dev->features |= NETIF_F_HIGHDMA |
			 NETIF_F_SG |
			 NETIF_F_FRAGLIST |
			 NETIF_F_HW_CSUM |
			 NETIF_F_TSO;
	dev->max_mtu = ETH_MAX_MTU;
}

static int nsim_validate(struct nlattr *tb[], struct nlattr *data[],
			 struct netlink_ext_ack *extack)
{
	if (tb[IFLA_ADDRESS]) {
		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
			return -EINVAL;
		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
			return -EADDRNOTAVAIL;
	}
	return 0;
}

static struct rtnl_link_ops nsim_link_ops __read_mostly = {
	.kind		= DRV_NAME,
	.priv_size	= sizeof(struct netdevsim),
	.setup		= nsim_setup,
	.validate	= nsim_validate,
};

static int __init nsim_module_init(void)
{
	return rtnl_link_register(&nsim_link_ops);
}

static void __exit nsim_module_exit(void)
{
	rtnl_link_unregister(&nsim_link_ops);
}

module_init(nsim_module_init);
module_exit(nsim_module_exit);
MODULE_LICENSE("GPL");
MODULE_ALIAS_RTNL_LINK(DRV_NAME);