/*********************************************************************
 *
 * Filename:      irlan_eth.c
 * Version:
 * Description:
 * Status:        Experimental.
 * Author:        Dag Brattli <dagb@cs.uit.no>
 * Created at:    Thu Oct 15 08:37:58 1998
 * Modified at:   Tue Mar 21 09:06:41 2000
 * Modified by:   Dag Brattli <dagb@cs.uit.no>
 * Sources:       skeleton.c by Donald Becker <becker@CESDIS.gsfc.nasa.gov>
 *                slip.c by Laurence Culhane,   <loz@holmes.demon.co.uk>
 *                          Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
 *
 *     Copyright (c) 1998-2000 Dag Brattli, All Rights Reserved.
 *
 *     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.
 *
 *     Neither Dag Brattli nor University of Tromsø admit liability nor
 *     provide warranty for any of this software. This material is
 *     provided "AS-IS" and at no charge.
 *
 ********************************************************************/

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/inetdevice.h>
#include <linux/if_arp.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <net/arp.h>

#include <net/irda/irda.h>
#include <net/irda/irmod.h>
#include <net/irda/irlan_common.h>
#include <net/irda/irlan_client.h>
#include <net/irda/irlan_event.h>
#include <net/irda/irlan_eth.h>

static int  irlan_eth_open(struct net_device *dev);
static int  irlan_eth_close(struct net_device *dev);
static netdev_tx_t  irlan_eth_xmit(struct sk_buff *skb,
                                         struct net_device *dev);
static void irlan_eth_set_multicast_list(struct net_device *dev);

static const struct net_device_ops irlan_eth_netdev_ops = {
        .ndo_open               = irlan_eth_open,
        .ndo_stop               = irlan_eth_close,
        .ndo_start_xmit         = irlan_eth_xmit,
        .ndo_set_rx_mode        = irlan_eth_set_multicast_list,
        .ndo_change_mtu         = eth_change_mtu,
        .ndo_validate_addr      = eth_validate_addr,
};

/*
 * Function irlan_eth_setup (dev)
 *
 *    The network device initialization function.
 *
 */
static void irlan_eth_setup(struct net_device *dev)
{
        ether_setup(dev);

        dev->netdev_ops         = &irlan_eth_netdev_ops;
        dev->destructor         = free_netdev;


        /*
         * Lets do all queueing in IrTTP instead of this device driver.
         * Queueing here as well can introduce some strange latency
         * problems, which we will avoid by setting the queue size to 0.
         */
        /*
         * The bugs in IrTTP and IrLAN that created this latency issue
         * have now been fixed, and we can propagate flow control properly
         * to the network layer. However, this requires a minimal queue of
         * packets for the device.
         * Without flow control, the Tx Queue is 14 (ttp) + 0 (dev) = 14
         * With flow control, the Tx Queue is 7 (ttp) + 4 (dev) = 11
         * See irlan_eth_flow_indication()...
         * Note : this number was randomly selected and would need to
         * be adjusted.
         * Jean II */
        dev->tx_queue_len = 4;
}

/*
 * Function alloc_irlandev
 *
 *    Allocate network device and control block
 *
 */
struct net_device *alloc_irlandev(const char *name)
{
        return alloc_netdev(sizeof(struct irlan_cb), name, NET_NAME_UNKNOWN,
                            irlan_eth_setup);
}

/*
 * Function irlan_eth_open (dev)
 *
 *    Network device has been opened by user
 *
 */
static int irlan_eth_open(struct net_device *dev)
{
        struct irlan_cb *self = netdev_priv(dev);

        /* Ready to play! */
        netif_stop_queue(dev); /* Wait until data link is ready */

        /* We are now open, so time to do some work */
        self->disconnect_reason = 0;
        irlan_client_wakeup(self, self->saddr, self->daddr);

        /* Make sure we have a hardware address before we return,
           so DHCP clients gets happy */
        return wait_event_interruptible(self->open_wait,
                                        !self->tsap_data->connected);
}

/*
 * Function irlan_eth_close (dev)
 *
 *    Stop the ether network device, his function will usually be called by
 *    ifconfig down. We should now disconnect the link, We start the
 *    close timer, so that the instance will be removed if we are unable
 *    to discover the remote device after the disconnect.
 */
static int irlan_eth_close(struct net_device *dev)
{
        struct irlan_cb *self = netdev_priv(dev);

        /* Stop device */
        netif_stop_queue(dev);

        irlan_close_data_channel(self);
        irlan_close_tsaps(self);

        irlan_do_client_event(self, IRLAN_LMP_DISCONNECT, NULL);
        irlan_do_provider_event(self, IRLAN_LMP_DISCONNECT, NULL);

        /* Remove frames queued on the control channel */
        skb_queue_purge(&self->client.txq);

        self->client.tx_busy = 0;

        return 0;
}

/*
 * Function irlan_eth_tx (skb)
 *
 *    Transmits ethernet frames over IrDA link.
 *
 */
static netdev_tx_t irlan_eth_xmit(struct sk_buff *skb,
                                        struct net_device *dev)
{
        struct irlan_cb *self = netdev_priv(dev);
        int ret;
        unsigned int len;

        /* skb headroom large enough to contain all IrDA-headers? */
        if ((skb_headroom(skb) < self->max_header_size) || (skb_shared(skb))) {
                struct sk_buff *new_skb =
                        skb_realloc_headroom(skb, self->max_header_size);

                /*  We have to free the original skb anyway */
                dev_kfree_skb(skb);

                /* Did the realloc succeed? */
                if (new_skb == NULL)
                        return NETDEV_TX_OK;

                /* Use the new skb instead */
                skb = new_skb;
        }

        dev->trans_start = jiffies;

        len = skb->len;
        /* Now queue the packet in the transport layer */
        if (self->use_udata)
                ret = irttp_udata_request(self->tsap_data, skb);
        else
                ret = irttp_data_request(self->tsap_data, skb);

        if (ret < 0) {
                /*
                 * IrTTPs tx queue is full, so we just have to
                 * drop the frame! You might think that we should
                 * just return -1 and don't deallocate the frame,
                 * but that is dangerous since it's possible that
                 * we have replaced the original skb with a new
                 * one with larger headroom, and that would really
                 * confuse do_dev_queue_xmit() in dev.c! I have
                 * tried :-) DB
                 */
                /* irttp_data_request already free the packet */
                dev->stats.tx_dropped++;
        } else {
                dev->stats.tx_packets++;
                dev->stats.tx_bytes += len;
        }

        return NETDEV_TX_OK;
}

/*
 * Function irlan_eth_receive (handle, skb)
 *
 *    This function gets the data that is received on the data channel
 *
 */
int irlan_eth_receive(void *instance, void *sap, struct sk_buff *skb)
{
        struct irlan_cb *self = instance;
        struct net_device *dev = self->dev;

        if (skb == NULL) {
                dev->stats.rx_dropped++;
                return 0;
        }
        if (skb->len < ETH_HLEN) {
                pr_debug("%s() : IrLAN frame too short (%d)\n",
                         __func__, skb->len);
                dev->stats.rx_dropped++;
                dev_kfree_skb(skb);
                return 0;
        }

        /*
         * Adopt this frame! Important to set all these fields since they
         * might have been previously set by the low level IrDA network
         * device driver
         */
        skb->protocol = eth_type_trans(skb, dev); /* Remove eth header */

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

        netif_rx(skb);   /* Eat it! */

        return 0;
}

/*
 * Function irlan_eth_flow (status)
 *
 *    Do flow control between IP/Ethernet and IrLAN/IrTTP. This is done by
 *    controlling the queue stop/start.
 *
 * The IrDA link layer has the advantage to have flow control, and
 * IrTTP now properly handles that. Flow controlling the higher layers
 * prevent us to drop Tx packets in here (up to 15% for a TCP socket,
 * more for UDP socket).
 * Also, this allow us to reduce the overall transmit queue, which means
 * less latency in case of mixed traffic.
 * Jean II
 */
void irlan_eth_flow_indication(void *instance, void *sap, LOCAL_FLOW flow)
{
        struct irlan_cb *self;
        struct net_device *dev;

        self = instance;

        IRDA_ASSERT(self != NULL, return;);
        IRDA_ASSERT(self->magic == IRLAN_MAGIC, return;);

        dev = self->dev;

        IRDA_ASSERT(dev != NULL, return;);

        pr_debug("%s() : flow %s ; running %d\n", __func__,
                 flow == FLOW_STOP ? "FLOW_STOP" : "FLOW_START",
                 netif_running(dev));

        switch (flow) {
        case FLOW_STOP:
                /* IrTTP is full, stop higher layers */
                netif_stop_queue(dev);
                break;
        case FLOW_START:
        default:
                /* Tell upper layers that its time to transmit frames again */
                /* Schedule network layer */
                netif_wake_queue(dev);
                break;
        }
}

/*
 * Function set_multicast_list (dev)
 *
 *    Configure the filtering of the device
 *
 */
#define HW_MAX_ADDRS 4 /* Must query to get it! */
static void irlan_eth_set_multicast_list(struct net_device *dev)
{
        struct irlan_cb *self = netdev_priv(dev);

        /* Check if data channel has been connected yet */
        if (self->client.state != IRLAN_DATA) {
                pr_debug("%s(), delaying!\n", __func__);
                return;
        }

        if (dev->flags & IFF_PROMISC) {
                /* Enable promiscuous mode */
                net_warn_ratelimited("Promiscuous mode not implemented by IrLAN!\n");
        } else if ((dev->flags & IFF_ALLMULTI) ||
                 netdev_mc_count(dev) > HW_MAX_ADDRS) {
                /* Disable promiscuous mode, use normal mode. */
                pr_debug("%s(), Setting multicast filter\n", __func__);
                /* hardware_set_filter(NULL); */

                irlan_set_multicast_filter(self, TRUE);
        } else if (!netdev_mc_empty(dev)) {
                pr_debug("%s(), Setting multicast filter\n", __func__);
                /* Walk the address list, and load the filter */
                /* hardware_set_filter(dev->mc_list); */

                irlan_set_multicast_filter(self, TRUE);
        } else {
                pr_debug("%s(), Clearing multicast filter\n", __func__);
                irlan_set_multicast_filter(self, FALSE);
        }

        if (dev->flags & IFF_BROADCAST)
                irlan_set_broadcast_filter(self, TRUE);
        else
                irlan_set_broadcast_filter(self, FALSE);
}