/*
 * Copyright (C) 2007-2010 B.A.T.M.A.N. contributors:
 *
 * Marek Lindner, Simon Wunderlich
 *
 * 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
 *
 */

#include "main.h"
#include "soft-interface.h"
#include "hard-interface.h"
#include "send.h"
#include "translation-table.h"
#include "types.h"
#include "hash.h"
#include <linux/slab.h>
#include <linux/ethtool.h>
#include <linux/etherdevice.h>

static uint16_t bcast_seqno = 1; /* give own bcast messages seq numbers to avoid
				  * broadcast storms */
static int32_t skb_packets;
static int32_t skb_bad_packets;

unsigned char mainIfAddr[ETH_ALEN];
static unsigned char mainIfAddr_default[ETH_ALEN];
static int bat_get_settings(struct net_device *dev, struct ethtool_cmd *cmd);
static void bat_get_drvinfo(struct net_device *dev,
			    struct ethtool_drvinfo *info);
static u32 bat_get_msglevel(struct net_device *dev);
static void bat_set_msglevel(struct net_device *dev, u32 value);
static u32 bat_get_link(struct net_device *dev);
static u32 bat_get_rx_csum(struct net_device *dev);
static int bat_set_rx_csum(struct net_device *dev, u32 data);

static const struct ethtool_ops bat_ethtool_ops = {
	.get_settings = bat_get_settings,
	.get_drvinfo = bat_get_drvinfo,
	.get_msglevel = bat_get_msglevel,
	.set_msglevel = bat_set_msglevel,
	.get_link = bat_get_link,
	.get_rx_csum = bat_get_rx_csum,
	.set_rx_csum = bat_set_rx_csum
};

void set_main_if_addr(uint8_t *addr)
{
	memcpy(mainIfAddr, addr, ETH_ALEN);
}

int main_if_was_up(void)
{
	return (memcmp(mainIfAddr, mainIfAddr_default, ETH_ALEN) != 0 ? 1 : 0);
}

int my_skb_push(struct sk_buff *skb, unsigned int len)
{
	int result = 0;

	skb_packets++;
	if (skb_headroom(skb) < len) {
		skb_bad_packets++;
		result = pskb_expand_head(skb, len, 0, GFP_ATOMIC);

		if (result < 0)
			return result;
	}

	skb_push(skb, len);
	return 0;
}

#ifdef HAVE_NET_DEVICE_OPS
static const struct net_device_ops bat_netdev_ops = {
	.ndo_open = interface_open,
	.ndo_stop = interface_release,
	.ndo_get_stats = interface_stats,
	.ndo_set_mac_address = interface_set_mac_addr,
	.ndo_change_mtu = interface_change_mtu,
	.ndo_start_xmit = interface_tx,
	.ndo_validate_addr = eth_validate_addr
};
#endif

void interface_setup(struct net_device *dev)
{
	struct bat_priv *priv = netdev_priv(dev);
	char dev_addr[ETH_ALEN];

	ether_setup(dev);

#ifdef HAVE_NET_DEVICE_OPS
	dev->netdev_ops = &bat_netdev_ops;
#else
	dev->open = interface_open;
	dev->stop = interface_release;
	dev->get_stats = interface_stats;
	dev->set_mac_address = interface_set_mac_addr;
	dev->change_mtu = interface_change_mtu;
	dev->hard_start_xmit = interface_tx;
#endif
	dev->destructor = free_netdev;

	dev->mtu = hardif_min_mtu();
	dev->hard_header_len = BAT_HEADER_LEN; /* reserve more space in the
						* skbuff for our header */

	/* generate random address */
	random_ether_addr(dev_addr);
	memcpy(dev->dev_addr, dev_addr, ETH_ALEN);

	SET_ETHTOOL_OPS(dev, &bat_ethtool_ops);

	memset(priv, 0, sizeof(struct bat_priv));
}

int interface_open(struct net_device *dev)
{
	netif_start_queue(dev);
	return 0;
}

int interface_release(struct net_device *dev)
{
	netif_stop_queue(dev);
	return 0;
}

struct net_device_stats *interface_stats(struct net_device *dev)
{
	struct bat_priv *priv = netdev_priv(dev);
	return &priv->stats;
}

int interface_set_mac_addr(struct net_device *dev, void *p)
{
	struct sockaddr *addr = p;

	if (!is_valid_ether_addr(addr->sa_data))
		return -EADDRNOTAVAIL;

	/* only modify hna-table if it has been initialised before */
	if (atomic_read(&module_state) == MODULE_ACTIVE) {
		hna_local_remove(dev->dev_addr, "mac address changed");
		hna_local_add(addr->sa_data);
	}

	memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);

	return 0;
}

int interface_change_mtu(struct net_device *dev, int new_mtu)
{
	/* check ranges */
	if ((new_mtu < 68) || (new_mtu > hardif_min_mtu()))
		return -EINVAL;

	dev->mtu = new_mtu;

	return 0;
}

int interface_tx(struct sk_buff *skb, struct net_device *dev)
{
	struct unicast_packet *unicast_packet;
	struct bcast_packet *bcast_packet;
	struct orig_node *orig_node;
	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
	struct bat_priv *priv = netdev_priv(dev);
	struct batman_if *batman_if;
	struct bat_priv *bat_priv;
	uint8_t dstaddr[6];
	int data_len = skb->len;
	unsigned long flags;

	if (atomic_read(&module_state) != MODULE_ACTIVE)
		goto dropped;

	/* FIXME: each batman_if will be attached to a softif */
	bat_priv = netdev_priv(soft_device);

	dev->trans_start = jiffies;
	/* TODO: check this for locks */
	hna_local_add(ethhdr->h_source);

	/* ethernet packet should be broadcasted */
	if (is_bcast(ethhdr->h_dest) || is_mcast(ethhdr->h_dest)) {

		if (my_skb_push(skb, sizeof(struct bcast_packet)) < 0)
			goto dropped;

		bcast_packet = (struct bcast_packet *)skb->data;
		bcast_packet->version = COMPAT_VERSION;

		/* batman packet type: broadcast */
		bcast_packet->packet_type = BAT_BCAST;

		/* hw address of first interface is the orig mac because only
		 * this mac is known throughout the mesh */
		memcpy(bcast_packet->orig, mainIfAddr, ETH_ALEN);

		/* set broadcast sequence number */
		bcast_packet->seqno = htons(bcast_seqno);

		/* broadcast packet. on success, increase seqno. */
		if (add_bcast_packet_to_list(skb) == NETDEV_TX_OK)
			bcast_seqno++;

		/* a copy is stored in the bcast list, therefore removing
		 * the original skb. */
		kfree_skb(skb);

	/* unicast packet */
	} else {
		spin_lock_irqsave(&orig_hash_lock, flags);
		/* get routing information */
		orig_node = ((struct orig_node *)hash_find(orig_hash,
							   ethhdr->h_dest));

		/* check for hna host */
		if (!orig_node)
			orig_node = transtable_search(ethhdr->h_dest);

		if ((orig_node) &&
		    (orig_node->router)) {
			struct neigh_node *router = orig_node->router;

			if (my_skb_push(skb, sizeof(struct unicast_packet)) < 0)
				goto unlock;

			unicast_packet = (struct unicast_packet *)skb->data;

			unicast_packet->version = COMPAT_VERSION;
			/* batman packet type: unicast */
			unicast_packet->packet_type = BAT_UNICAST;
			/* set unicast ttl */
			unicast_packet->ttl = TTL;
			/* copy the destination for faster routing */
			memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);

			/* net_dev won't be available when not active */
			if (router->if_incoming->if_status != IF_ACTIVE)
				goto unlock;

			/* don't lock while sending the packets ... we therefore
			 * copy the required data before sending */

			batman_if = router->if_incoming;
			memcpy(dstaddr, router->addr, ETH_ALEN);
			spin_unlock_irqrestore(&orig_hash_lock, flags);

			send_skb_packet(skb, batman_if, dstaddr);
		} else {
			goto unlock;
		}
	}

	priv->stats.tx_packets++;
	priv->stats.tx_bytes += data_len;
	goto end;

unlock:
	spin_unlock_irqrestore(&orig_hash_lock, flags);
dropped:
	priv->stats.tx_dropped++;
	kfree_skb(skb);
end:
	return NETDEV_TX_OK;
}

void interface_rx(struct sk_buff *skb, int hdr_size)
{
	struct net_device *dev = soft_device;
	struct bat_priv *priv = netdev_priv(dev);

	/* check if enough space is available for pulling, and pull */
	if (!pskb_may_pull(skb, hdr_size)) {
		kfree_skb(skb);
		return;
	}
	skb_pull_rcsum(skb, hdr_size);
/*	skb_set_mac_header(skb, -sizeof(struct ethhdr));*/

	if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) {
		kfree_skb(skb);
		return;
	}
	skb->dev = dev;
	skb->protocol = eth_type_trans(skb, dev);

	/* should not be neccesary anymore as we use skb_pull_rcsum()
	 * TODO: please verify this and remove this TODO
	 * -- Dec 21st 2009, Simon Wunderlich */

/*	skb->ip_summed = CHECKSUM_UNNECESSARY;*/

	/* TODO: set skb->pkt_type to PACKET_BROADCAST, PACKET_MULTICAST,
	 * PACKET_OTHERHOST or PACKET_HOST */

	priv->stats.rx_packets++;
	priv->stats.rx_bytes += skb->len;

	dev->last_rx = jiffies;

	netif_rx(skb);
}

/* ethtool */
static int bat_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
	cmd->supported = 0;
	cmd->advertising = 0;
	cmd->speed = SPEED_10;
	cmd->duplex = DUPLEX_FULL;
	cmd->port = PORT_TP;
	cmd->phy_address = 0;
	cmd->transceiver = XCVR_INTERNAL;
	cmd->autoneg = AUTONEG_DISABLE;
	cmd->maxtxpkt = 0;
	cmd->maxrxpkt = 0;

	return 0;
}

static void bat_get_drvinfo(struct net_device *dev,
			    struct ethtool_drvinfo *info)
{
	strcpy(info->driver, "B.A.T.M.A.N. advanced");
	strcpy(info->version, SOURCE_VERSION);
	strcpy(info->fw_version, "N/A");
	strcpy(info->bus_info, "batman");
}

static u32 bat_get_msglevel(struct net_device *dev)
{
	return -EOPNOTSUPP;
}

static void bat_set_msglevel(struct net_device *dev, u32 value)
{
}

static u32 bat_get_link(struct net_device *dev)
{
	return 1;
}

static u32 bat_get_rx_csum(struct net_device *dev)
{
	return 0;
}

static int bat_set_rx_csum(struct net_device *dev, u32 data)
{
	return -EOPNOTSUPP;
}