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/*********************************************************************
 *                
 * 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 Troms admit liability nor
 *     provide warranty for any of this software. This material is 
 *     provided "AS-IS" and at no charge.
 *     
 ********************************************************************/

#include <linux/config.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/inetdevice.h>
#include <linux/if_arp.h>
#include <linux/module.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 int  irlan_eth_xmit(struct sk_buff *skb, struct net_device *dev);
static void irlan_eth_set_multicast_list( struct net_device *dev);
static struct net_device_stats *irlan_eth_get_stats(struct net_device *dev);

/*
 * Function irlan_eth_setup (dev)
 *
 *    The network device initialization function.
 *
 */
static void irlan_eth_setup(struct net_device *dev)
{
	dev->open               = irlan_eth_open;
	dev->stop               = irlan_eth_close;
	dev->hard_start_xmit    = irlan_eth_xmit; 
	dev->get_stats	        = irlan_eth_get_stats;
	dev->set_multicast_list = irlan_eth_set_multicast_list;
	dev->destructor		= free_netdev;

	SET_MODULE_OWNER(dev);

	ether_setup(dev);
	
	/* 
	 * 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,
			    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);
	
	IRDA_DEBUG(2, "%s()\n", __FUNCTION__ );

	/* 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);
	
	IRDA_DEBUG(2, "%s()\n", __FUNCTION__ );
	
	/* 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 int irlan_eth_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct irlan_cb *self = netdev_priv(dev);
	int ret;

	/* 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 0;

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

	dev->trans_start = jiffies;

	/* 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 */
		self->stats.tx_dropped++;
	} else {
		self->stats.tx_packets++;
		self->stats.tx_bytes += skb->len; 
	}
	
	return 0;
}

/*
 * 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;

	if (skb == NULL) {
		++self->stats.rx_dropped; 
		return 0;
	}
	if (skb->len < ETH_HLEN) {
		IRDA_DEBUG(0, "%s() : IrLAN frame too short (%d)\n",
			   __FUNCTION__, skb->len);
		++self->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->dev = self->dev;
	skb->protocol=eth_type_trans(skb, skb->dev); /* Remove eth header */
	
	self->stats.rx_packets++;
	self->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 = (struct irlan_cb *) instance;

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

	IRDA_ASSERT(dev != NULL, return;);
	
	IRDA_DEBUG(0, "%s() : flow %s ; running %d\n", __FUNCTION__,
		   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 irlan_etc_send_gratuitous_arp (dev)
 *
 *    Send gratuitous ARP to announce that we have changed
 *    hardware address, so that all peers updates their ARP tables
 */
void irlan_eth_send_gratuitous_arp(struct net_device *dev)
{
	struct in_device *in_dev;

	/* 
	 * When we get a new MAC address do a gratuitous ARP. This
	 * is useful if we have changed access points on the same
	 * subnet.  
	 */
#ifdef CONFIG_INET
	IRDA_DEBUG(4, "IrLAN: Sending gratuitous ARP\n");
	rcu_read_lock();
	in_dev = __in_dev_get(dev);
	if (in_dev == NULL)
		goto out;
	if (in_dev->ifa_list)
		
	arp_send(ARPOP_REQUEST, ETH_P_ARP, 
		 in_dev->ifa_list->ifa_address,
		 dev, 
		 in_dev->ifa_list->ifa_address,
		 NULL, dev->dev_addr, NULL);
out:
	rcu_read_unlock();
#endif /* CONFIG_INET */
}

/*
 * 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);

	IRDA_DEBUG(2, "%s()\n", __FUNCTION__ );

	/* Check if data channel has been connected yet */
	if (self->client.state != IRLAN_DATA) {
		IRDA_DEBUG(1, "%s(), delaying!\n", __FUNCTION__ );
		return;
	}

	if (dev->flags & IFF_PROMISC) {
		/* Enable promiscuous mode */
		IRDA_WARNING("Promiscous mode not implemented by IrLAN!\n");
	} 
	else if ((dev->flags & IFF_ALLMULTI) || dev->mc_count > HW_MAX_ADDRS) {
		/* Disable promiscuous mode, use normal mode. */
		IRDA_DEBUG(4, "%s(), Setting multicast filter\n", __FUNCTION__ );
		/* hardware_set_filter(NULL); */

		irlan_set_multicast_filter(self, TRUE);
	}
	else if (dev->mc_count) {
		IRDA_DEBUG(4, "%s(), Setting multicast filter\n", __FUNCTION__ );
		/* Walk the address list, and load the filter */
		/* hardware_set_filter(dev->mc_list); */

		irlan_set_multicast_filter(self, TRUE);
	}
	else {
		IRDA_DEBUG(4, "%s(), Clearing multicast filter\n", __FUNCTION__ );
		irlan_set_multicast_filter(self, FALSE);
	}

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

/*
 * Function irlan_get_stats (dev)
 *
 *    Get the current statistics for this device
 *
 */
static struct net_device_stats *irlan_eth_get_stats(struct net_device *dev) 
{
	struct irlan_cb *self = netdev_priv(dev);

	return &self->stats;
}