lec.c

/*
 * lec.c: Lan Emulation driver
 *
 * Marko Kiiskila <mkiiskila@yahoo.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/capability.h>

/* We are ethernet device */
#include <linux/if_ether.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <net/sock.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <asm/byteorder.h>
#include <linux/uaccess.h>
#include <net/arp.h>
#include <net/dst.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/seq_file.h>

/* And atm device */
#include <linux/atmdev.h>
#include <linux/atmlec.h>

/* Proxy LEC knows about bridging */
#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
#include "../bridge/br_private.h"

static unsigned char bridge_ula_lec[] = { 0x01, 0x80, 0xc2, 0x00, 0x00 };
#endif

/* Modular too */
#include <linux/module.h>
#include <linux/init.h>

#include "lec.h"
#include "lec_arpc.h"
#include "resources.h"

#define DUMP_PACKETS 0		/*
				 * 0 = None,
				 * 1 = 30 first bytes
				 * 2 = Whole packet
				 */

#define LEC_UNRES_QUE_LEN 8	/*
				 * number of tx packets to queue for a
				 * single destination while waiting for SVC
				 */

static int lec_open(struct net_device *dev);
static netdev_tx_t lec_start_xmit(struct sk_buff *skb,
				  struct net_device *dev);
static int lec_close(struct net_device *dev);
static struct lec_arp_table *lec_arp_find(struct lec_priv *priv,
					  const unsigned char *mac_addr);
static int lec_arp_remove(struct lec_priv *priv,
			  struct lec_arp_table *to_remove);
/* LANE2 functions */
static void lane2_associate_ind(struct net_device *dev, const u8 *mac_address,
				const u8 *tlvs, u32 sizeoftlvs);
static int lane2_resolve(struct net_device *dev, const u8 *dst_mac, int force,
			 u8 **tlvs, u32 *sizeoftlvs);
static int lane2_associate_req(struct net_device *dev, const u8 *lan_dst,
			       const u8 *tlvs, u32 sizeoftlvs);

static int lec_addr_delete(struct lec_priv *priv, const unsigned char *atm_addr,
			   unsigned long permanent);
static void lec_arp_check_empties(struct lec_priv *priv,
				  struct atm_vcc *vcc, struct sk_buff *skb);
static void lec_arp_destroy(struct lec_priv *priv);
static void lec_arp_init(struct lec_priv *priv);
static struct atm_vcc *lec_arp_resolve(struct lec_priv *priv,
				       const unsigned char *mac_to_find,
				       int is_rdesc,
				       struct lec_arp_table **ret_entry);
static void lec_arp_update(struct lec_priv *priv, const unsigned char *mac_addr,
			   const unsigned char *atm_addr,
			   unsigned long remoteflag,
			   unsigned int targetless_le_arp);
static void lec_flush_complete(struct lec_priv *priv, unsigned long tran_id);
static int lec_mcast_make(struct lec_priv *priv, struct atm_vcc *vcc);
static void lec_set_flush_tran_id(struct lec_priv *priv,
				  const unsigned char *atm_addr,
				  unsigned long tran_id);
static void lec_vcc_added(struct lec_priv *priv,
			  const struct atmlec_ioc *ioc_data,
			  struct atm_vcc *vcc,
			  void (*old_push)(struct atm_vcc *vcc,
					   struct sk_buff *skb));
static void lec_vcc_close(struct lec_priv *priv, struct atm_vcc *vcc);

/* must be done under lec_arp_lock */
static inline void lec_arp_hold(struct lec_arp_table *entry)
{
	atomic_inc(&entry->usage);
}

static inline void lec_arp_put(struct lec_arp_table *entry)
{
	if (atomic_dec_and_test(&entry->usage))
		kfree(entry);
}

static struct lane2_ops lane2_ops = {
	lane2_resolve,		/* resolve,             spec 3.1.3 */
	lane2_associate_req,	/* associate_req,       spec 3.1.4 */
	NULL			/* associate indicator, spec 3.1.5 */
};

static unsigned char bus_mac[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

/* Device structures */
static struct net_device *dev_lec[MAX_LEC_ITF];

#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
static void lec_handle_bridge(struct sk_buff *skb, struct net_device *dev)
{
	char *buff;
	struct lec_priv *priv;

	/*
	 * Check if this is a BPDU. If so, ask zeppelin to send
	 * LE_TOPOLOGY_REQUEST with the same value of Topology Change bit
	 * as the Config BPDU has
	 */
	buff = skb->data + skb->dev->hard_header_len;
	if (*buff++ == 0x42 && *buff++ == 0x42 && *buff++ == 0x03) {
		struct sock *sk;
		struct sk_buff *skb2;
		struct atmlec_msg *mesg;

		skb2 = alloc_skb(sizeof(struct atmlec_msg), GFP_ATOMIC);
		if (skb2 == NULL)
			return;
		skb2->len = sizeof(struct atmlec_msg);
		mesg = (struct atmlec_msg *)skb2->data;
		mesg->type = l_topology_change;
		buff += 4;
		mesg->content.normal.flag = *buff & 0x01;
					/* 0x01 is topology change */

		priv = netdev_priv(dev);
		atm_force_charge(priv->lecd, skb2->truesize);
		sk = sk_atm(priv->lecd);
		skb_queue_tail(&sk->sk_receive_queue, skb2);
		sk->sk_data_ready(sk);
	}
}
#endif /* defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) */

/*
 * Open/initialize the netdevice. This is called (in the current kernel)
 * sometime after booting when the 'ifconfig' program is run.
 *
 * This routine should set everything up anew at each open, even
 * registers that "should" only need to be set once at boot, so that
 * there is non-reboot way to recover if something goes wrong.
 */

static int lec_open(struct net_device *dev)
{
	netif_start_queue(dev);

	return 0;
}

static void
lec_send(struct atm_vcc *vcc, struct sk_buff *skb)
{
	struct net_device *dev = skb->dev;

	ATM_SKB(skb)->vcc = vcc;
	ATM_SKB(skb)->atm_options = vcc->atm_options;

	atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
	if (vcc->send(vcc, skb) < 0) {
		dev->stats.tx_dropped++;
		return;
	}

	dev->stats.tx_packets++;
	dev->stats.tx_bytes += skb->len;
}

static void lec_tx_timeout(struct net_device *dev)
{
	pr_info("%s\n", dev->name);
	dev->trans_start = jiffies;
	netif_wake_queue(dev);
}

static netdev_tx_t lec_start_xmit(struct sk_buff *skb,
				  struct net_device *dev)
{
	struct sk_buff *skb2;
	struct lec_priv *priv = netdev_priv(dev);
	struct lecdatahdr_8023 *lec_h;
	struct atm_vcc *vcc;
	struct lec_arp_table *entry;
	unsigned char *dst;
	int min_frame_size;
	int is_rdesc;

	pr_debug("called\n");
	if (!priv->lecd) {
		pr_info("%s:No lecd attached\n", dev->name);
		dev->stats.tx_errors++;
		netif_stop_queue(dev);
		kfree_skb(skb);
		return NETDEV_TX_OK;
	}

	pr_debug("skbuff head:%lx data:%lx tail:%lx end:%lx\n",
		 (long)skb->head, (long)skb->data, (long)skb_tail_pointer(skb),
		 (long)skb_end_pointer(skb));
#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
	if (memcmp(skb->data, bridge_ula_lec, sizeof(bridge_ula_lec)) == 0)
		lec_handle_bridge(skb, dev);
#endif

	/* Make sure we have room for lec_id */
	if (skb_headroom(skb) < 2) {
		pr_debug("reallocating skb\n");
		skb2 = skb_realloc_headroom(skb, LEC_HEADER_LEN);
		if (unlikely(!skb2)) {
			kfree_skb(skb);
			return NETDEV_TX_OK;
		}
		consume_skb(skb);
		skb = skb2;
	}
	skb_push(skb, 2);

	/* Put le header to place */
	lec_h = (struct lecdatahdr_8023 *)skb->data;
	lec_h->le_header = htons(priv->lecid);

#if DUMP_PACKETS >= 2
#define MAX_DUMP_SKB 99
#elif DUMP_PACKETS >= 1
#define MAX_DUMP_SKB 30
#endif
#if DUMP_PACKETS >= 1
	printk(KERN_DEBUG "%s: send datalen:%ld lecid:%4.4x\n",
	       dev->name, skb->len, priv->lecid);
	print_hex_dump(KERN_DEBUG, "", DUMP_OFFSET, 16, 1,
		       skb->data, min(skb->len, MAX_DUMP_SKB), true);
#endif /* DUMP_PACKETS >= 1 */

	/* Minimum ethernet-frame size */
	min_frame_size = LEC_MINIMUM_8023_SIZE;
	if (skb->len < min_frame_size) {
		if ((skb->len + skb_tailroom(skb)) < min_frame_size) {
			skb2 = skb_copy_expand(skb, 0,
					       min_frame_size - skb->truesize,
					       GFP_ATOMIC);
			dev_kfree_skb(skb);
			if (skb2 == NULL) {
				dev->stats.tx_dropped++;
				return NETDEV_TX_OK;
			}
			skb = skb2;
		}
		skb_put(skb, min_frame_size - skb->len);
	}

	/* Send to right vcc */
	is_rdesc = 0;
	dst = lec_h->h_dest;
	entry = NULL;
	vcc = lec_arp_resolve(priv, dst, is_rdesc, &entry);
	pr_debug("%s:vcc:%p vcc_flags:%lx, entry:%p\n",
		 dev->name, vcc, vcc ? vcc->flags : 0, entry);
	if (!vcc || !test_bit(ATM_VF_READY, &vcc->flags)) {
		if (entry && (entry->tx_wait.qlen < LEC_UNRES_QUE_LEN)) {
			pr_debug("%s:queuing packet, MAC address %pM\n",
				 dev->name, lec_h->h_dest);
			skb_queue_tail(&entry->tx_wait, skb);
		} else {
			pr_debug("%s:tx queue full or no arp entry, dropping, MAC address: %pM\n",
				 dev->name, lec_h->h_dest);
			dev->stats.tx_dropped++;
			dev_kfree_skb(skb);
		}
		goto out;
	}
#if DUMP_PACKETS > 0
	printk(KERN_DEBUG "%s:sending to vpi:%d vci:%d\n",
	       dev->name, vcc->vpi, vcc->vci);
#endif /* DUMP_PACKETS > 0 */

	while (entry && (skb2 = skb_dequeue(&entry->tx_wait))) {
		pr_debug("emptying tx queue, MAC address %pM\n", lec_h->h_dest);
		lec_send(vcc, skb2);
	}

	lec_send(vcc, skb);

	if (!atm_may_send(vcc, 0)) {
		struct lec_vcc_priv *vpriv = LEC_VCC_PRIV(vcc);

		vpriv->xoff = 1;
		netif_stop_queue(dev);

		/*
		 * vcc->pop() might have occurred in between, making
		 * the vcc usuable again.  Since xmit is serialized,
		 * this is the only situation we have to re-test.
		 */

		if (atm_may_send(vcc, 0))
			netif_wake_queue(dev);
	}

out:
	if (entry)
		lec_arp_put(entry);
	dev->trans_start = jiffies;
	return NETDEV_TX_OK;
}

/* The inverse routine to net_open(). */
static int lec_close(struct net_device *dev)
{
	netif_stop_queue(dev);
	return 0;
}

static int lec_atm_send(struct atm_vcc *vcc, struct sk_buff *skb)
{
	unsigned long flags;
	struct net_device *dev = (struct net_device *)vcc->proto_data;
	struct lec_priv *priv = netdev_priv(dev);
	struct atmlec_msg *mesg;
	struct lec_arp_table *entry;
	int i;
	char *tmp;		/* FIXME */

	atomic_sub(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
	mesg = (struct atmlec_msg *)skb->data;
	tmp = skb->data;
	tmp += sizeof(struct atmlec_msg);
	pr_debug("%s: msg from zeppelin:%d\n", dev->name, mesg->type);
	switch (mesg->type) {
	case l_set_mac_addr:
		for (i = 0; i < 6; i++)
			dev->dev_addr[i] = mesg->content.normal.mac_addr[i];
		break;
	case l_del_mac_addr:
		for (i = 0; i < 6; i++)
			dev->dev_addr[i] = 0;
		break;
	case l_addr_delete:
		lec_addr_delete(priv, mesg->content.normal.atm_addr,
				mesg->content.normal.flag);
		break;
	case l_topology_change:
		priv->topology_change = mesg->content.normal.flag;
		break;
	case l_flush_complete:
		lec_flush_complete(priv, mesg->content.normal.flag);
		break;
	case l_narp_req:	/* LANE2: see 7.1.35 in the lane2 spec */
		spin_lock_irqsave(&priv->lec_arp_lock, flags);
		entry = lec_arp_find(priv, mesg->content.normal.mac_addr);
		lec_arp_remove(priv, entry);
		spin_unlock_irqrestore(&priv->lec_arp_lock, flags);

		if (mesg->content.normal.no_source_le_narp)
			break;
		/* FALL THROUGH */
	case l_arp_update:
		lec_arp_update(priv, mesg->content.normal.mac_addr,
			       mesg->content.normal.atm_addr,
			       mesg->content.normal.flag,
			       mesg->content.normal.targetless_le_arp);
		pr_debug("in l_arp_update\n");
		if (mesg->sizeoftlvs != 0) {	/* LANE2 3.1.5 */
			pr_debug("LANE2 3.1.5, got tlvs, size %d\n",
				 mesg->sizeoftlvs);
			lane2_associate_ind(dev, mesg->content.normal.mac_addr,
					    tmp, mesg->sizeoftlvs);
		}
		break;
	case l_config:
		priv->maximum_unknown_frame_count =
		    mesg->content.config.maximum_unknown_frame_count;
		priv->max_unknown_frame_time =
		    (mesg->content.config.max_unknown_frame_time * HZ);
		priv->max_retry_count = mesg->content.config.max_retry_count;
		priv->aging_time = (mesg->content.config.aging_time * HZ);
		priv->forward_delay_time =
		    (mesg->content.config.forward_delay_time * HZ);
		priv->arp_response_time =
		    (mesg->content.config.arp_response_time * HZ);
		priv->flush_timeout = (mesg->content.config.flush_timeout * HZ);
		priv->path_switching_delay =
		    (mesg->content.config.path_switching_delay * HZ);
		priv->lane_version = mesg->content.config.lane_version;
					/* LANE2 */
		priv->lane2_ops = NULL;
		if (priv->lane_version > 1)
			priv->lane2_ops = &lane2_ops;
		if (dev_set_mtu(dev, mesg->content.config.mtu))
			pr_info("%s: change_mtu to %d failed\n",
				dev->name, mesg->content.config.mtu);
		priv->is_proxy = mesg->content.config.is_proxy;
		break;
	case l_flush_tran_id:
		lec_set_flush_tran_id(priv, mesg->content.normal.atm_addr,
				      mesg->content.normal.flag);
		break;
	case l_set_lecid:
		priv->lecid =
		    (unsigned short)(0xffff & mesg->content.normal.flag);
		break;
	case l_should_bridge:
#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
	{
		pr_debug("%s: bridge zeppelin asks about %pM\n",
			 dev->name, mesg->content.proxy.mac_addr);

		if (br_fdb_test_addr_hook == NULL)
			break;

		if (br_fdb_test_addr_hook(dev, mesg->content.proxy.mac_addr)) {
			/* hit from bridge table, send LE_ARP_RESPONSE */
			struct sk_buff *skb2;
			struct sock *sk;

			pr_debug("%s: entry found, responding to zeppelin\n",
				 dev->name);
			skb2 = alloc_skb(sizeof(struct atmlec_msg), GFP_ATOMIC);
			if (skb2 == NULL)
				break;
			skb2->len = sizeof(struct atmlec_msg);
			skb_copy_to_linear_data(skb2, mesg, sizeof(*mesg));
			atm_force_charge(priv->lecd, skb2->truesize);
			sk = sk_atm(priv->lecd);
			skb_queue_tail(&sk->sk_receive_queue, skb2);
			sk->sk_data_ready(sk);
		}
	}
#endif /* defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) */
		break;
	default:
		pr_info("%s: Unknown message type %d\n", dev->name, mesg->type);
		dev_kfree_skb(skb);
		return -EINVAL;
	}
	dev_kfree_skb(skb);
	return 0;
}

static void lec_atm_close(struct atm_vcc *vcc)
{
	struct sk_buff *skb;
	struct net_device *dev = (struct net_device *)vcc->proto_data;
	struct lec_priv *priv = netdev_priv(dev);

	priv->lecd = NULL;
	/* Do something needful? */

	netif_stop_queue(dev);
	lec_arp_destroy(priv);

	if (skb_peek(&sk_atm(vcc)->sk_receive_queue))
		pr_info("%s closing with messages pending\n", dev->name);
	while ((skb = skb_dequeue(&sk_atm(vcc)->sk_receive_queue))) {
		atm_return(vcc, skb->truesize);
		dev_kfree_skb(skb);
	}

	pr_info("%s: Shut down!\n", dev->name);
	module_put(THIS_MODULE);
}

static struct atmdev_ops lecdev_ops = {
	.close = lec_atm_close,
	.send = lec_atm_send
};

static struct atm_dev lecatm_dev = {
	.ops = &lecdev_ops,
	.type = "lec",
	.number = 999,		/* dummy device number */
	.lock = __SPIN_LOCK_UNLOCKED(lecatm_dev.lock)
};

/*
 * LANE2: new argument struct sk_buff *data contains
 * the LE_ARP based TLVs introduced in the LANE2 spec
 */
static int
send_to_lecd(struct lec_priv *priv, atmlec_msg_type type,
	     const unsigned char *mac_addr, const unsigned char *atm_addr,
	     struct sk_buff *data)
{
	struct sock *sk;
	struct sk_buff *skb;
	struct atmlec_msg *mesg;

	if (!priv || !priv->lecd)
		return -1;
	skb = alloc_skb(sizeof(struct atmlec_msg), GFP_ATOMIC);
	if (!skb)
		return -1;
	skb->len = sizeof(struct atmlec_msg);
	mesg = (struct atmlec_msg *)skb->data;
	memset(mesg, 0, sizeof(struct atmlec_msg));
	mesg->type = type;
	if (data != NULL)
		mesg->sizeoftlvs = data->len;
	if (mac_addr)
		ether_addr_copy(mesg->content.normal.mac_addr, mac_addr);
	else
		mesg->content.normal.targetless_le_arp = 1;
	if (atm_addr)
		memcpy(&mesg->content.normal.atm_addr, atm_addr, ATM_ESA_LEN);

	atm_force_charge(priv->lecd, skb->truesize);
	sk = sk_atm(priv->lecd);
	skb_queue_tail(&sk->sk_receive_queue, skb);
	sk->sk_data_ready(sk);

	if (data != NULL) {
		pr_debug("about to send %d bytes of data\n", data->len);
		atm_force_charge(priv->lecd, data->truesize);
		skb_queue_tail(&sk->sk_receive_queue, data);
		sk->sk_data_ready(sk);
	}

	return 0;
}

/* shamelessly stolen from drivers/net/net_init.c */
static int lec_change_mtu(struct net_device *dev, int new_mtu)
{
	if ((new_mtu < 68) || (new_mtu > 18190))
		return -EINVAL;
	dev->mtu = new_mtu;
	return 0;
}

static void lec_set_multicast_list(struct net_device *dev)
{
	/*
	 * by default, all multicast frames arrive over the bus.
	 * eventually support selective multicast service
	 */
}

static const struct net_device_ops lec_netdev_ops = {
	.ndo_open		= lec_open,
	.ndo_stop		= lec_close,
	.ndo_start_xmit		= lec_start_xmit,
	.ndo_change_mtu		= lec_change_mtu,
	.ndo_tx_timeout		= lec_tx_timeout,
	.ndo_set_rx_mode	= lec_set_multicast_list,
};

static const unsigned char lec_ctrl_magic[] = {
	0xff,
	0x00,
	0x01,
	0x01
};

#define LEC_DATA_DIRECT_8023  2
#define LEC_DATA_DIRECT_8025  3

static int lec_is_data_direct(struct atm_vcc *vcc)
{
	return ((vcc->sap.blli[0].l3.tr9577.snap[4] == LEC_DATA_DIRECT_8023) ||
		(vcc->sap.blli[0].l3.tr9577.snap[4] == LEC_DATA_DIRECT_8025));
}

static void lec_push(struct atm_vcc *vcc, struct sk_buff *skb)
{
	unsigned long flags;
	struct net_device *dev = (struct net_device *)vcc->proto_data;
	struct lec_priv *priv = netdev_priv(dev);

#if DUMP_PACKETS > 0
	printk(KERN_DEBUG "%s: vcc vpi:%d vci:%d\n",
	       dev->name, vcc->vpi, vcc->vci);
#endif
	if (!skb) {
		pr_debug("%s: null skb\n", dev->name);
		lec_vcc_close(priv, vcc);
		return;
	}
#if DUMP_PACKETS >= 2
#define MAX_SKB_DUMP 99
#elif DUMP_PACKETS >= 1
#define MAX_SKB_DUMP 30
#endif
#if DUMP_PACKETS > 0
	printk(KERN_DEBUG "%s: rcv datalen:%ld lecid:%4.4x\n",
	       dev->name, skb->len, priv->lecid);
	print_hex_dump(KERN_DEBUG, "", DUMP_OFFSET, 16, 1,
		       skb->data, min(MAX_SKB_DUMP, skb->len), true);
#endif /* DUMP_PACKETS > 0 */
	if (memcmp(skb->data, lec_ctrl_magic, 4) == 0) {
				/* Control frame, to daemon */
		struct sock *sk = sk_atm(vcc);

		pr_debug("%s: To daemon\n", dev->name);
		skb_queue_tail(&sk->sk_receive_queue, skb);
		sk->sk_data_ready(sk);
	} else {		/* Data frame, queue to protocol handlers */
		struct lec_arp_table *entry;
		unsigned char *src, *dst;

		atm_return(vcc, skb->truesize);
		if (*(__be16 *) skb->data == htons(priv->lecid) ||
		    !priv->lecd || !(dev->flags & IFF_UP)) {
			/*
			 * Probably looping back, or if lecd is missing,
			 * lecd has gone down
			 */
			pr_debug("Ignoring frame...\n");
			dev_kfree_skb(skb);
			return;
		}
		dst = ((struct lecdatahdr_8023 *)skb->data)->h_dest;

		/*
		 * If this is a Data Direct VCC, and the VCC does not match
		 * the LE_ARP cache entry, delete the LE_ARP cache entry.
		 */
		spin_lock_irqsave(&priv->lec_arp_lock, flags);
		if (lec_is_data_direct(vcc)) {
			src = ((struct lecdatahdr_8023 *)skb->data)->h_source;
			entry = lec_arp_find(priv, src);
			if (entry && entry->vcc != vcc) {
				lec_arp_remove(priv, entry);
				lec_arp_put(entry);
			}
		}
		spin_unlock_irqrestore(&priv->lec_arp_lock, flags);

		if (!(dst[0] & 0x01) &&	/* Never filter Multi/Broadcast */
		    !priv->is_proxy &&	/* Proxy wants all the packets */
		    memcmp(dst, dev->dev_addr, dev->addr_len)) {
			dev_kfree_skb(skb);
			return;
		}
		if (!hlist_empty(&priv->lec_arp_empty_ones))
			lec_arp_check_empties(priv, vcc, skb);
		skb_pull(skb, 2);	/* skip lec_id */
		skb->protocol = eth_type_trans(skb, dev);
		dev->stats.rx_packets++;
		dev->stats.rx_bytes += skb->len;
		memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
		netif_rx(skb);
	}
}

static void lec_pop(struct atm_vcc *vcc, struct sk_buff *skb)
{
	struct lec_vcc_priv *vpriv = LEC_VCC_PRIV(vcc);
	struct net_device *dev = skb->dev;

	if (vpriv == NULL) {
		pr_info("vpriv = NULL!?!?!?\n");
		return;
	}

	vpriv->old_pop(vcc, skb);

	if (vpriv->xoff && atm_may_send(vcc, 0)) {
		vpriv->xoff = 0;
		if (netif_running(dev) && netif_queue_stopped(dev))
			netif_wake_queue(dev);
	}
}

static int lec_vcc_attach(struct atm_vcc *vcc, void __user *arg)
{
	struct lec_vcc_priv *vpriv;
	int bytes_left;
	struct atmlec_ioc ioc_data;

	/* Lecd must be up in this case */
	bytes_left = copy_from_user(&ioc_data, arg, sizeof(struct atmlec_ioc));
	if (bytes_left != 0)
		pr_info("copy from user failed for %d bytes\n", bytes_left);
	if (ioc_data.dev_num < 0 || ioc_data.dev_num >= MAX_LEC_ITF ||
	    !dev_lec[ioc_data.dev_num])
		return -EINVAL;
	vpriv = kmalloc(sizeof(struct lec_vcc_priv), GFP_KERNEL);
	if (!vpriv)
		return -ENOMEM;
	vpriv->xoff = 0;
	vpriv->old_pop = vcc->pop;
	vcc->user_back = vpriv;
	vcc->pop = lec_pop;
	lec_vcc_added(netdev_priv(dev_lec[ioc_data.dev_num]),
		      &ioc_data, vcc, vcc->push);
	vcc->proto_data = dev_lec[ioc_data.dev_num];
	vcc->push = lec_push;
	return 0;
}

static int lec_mcast_attach(struct atm_vcc *vcc, int arg)
{
	if (arg < 0 || arg >= MAX_LEC_ITF || !dev_lec[arg])
		return -EINVAL;
	vcc->proto_data = dev_lec[arg];
	return lec_mcast_make(netdev_priv(dev_lec[arg]), vcc);
}

/* Initialize device. */
static int lecd_attach(struct atm_vcc *vcc, int arg)
{
	int i;
	struct lec_priv *priv;

	if (arg < 0)
		i = 0;
	else
		i = arg;
	if (arg >= MAX_LEC_ITF)
		return -EINVAL;
	if (!dev_lec[i]) {
		int size;

		size = sizeof(struct lec_priv);
		dev_lec[i] = alloc_etherdev(size);
		if (!dev_lec[i])
			return -ENOMEM;
		dev_lec[i]->netdev_ops = &lec_netdev_ops;
		snprintf(dev_lec[i]->name, IFNAMSIZ, "lec%d", i);
		if (register_netdev(dev_lec[i])) {
			free_netdev(dev_lec[i]);
			return -EINVAL;
		}

		priv = netdev_priv(dev_lec[i]);
	} else {
		priv = netdev_priv(dev_lec[i]);
		if (priv->lecd)
			return -EADDRINUSE;
	}
	lec_arp_init(priv);
	priv->itfnum = i;	/* LANE2 addition */
	priv->lecd = vcc;
	vcc->dev = &lecatm_dev;
	vcc_insert_socket(sk_atm(vcc));

	vcc->proto_data = dev_lec[i];
	set_bit(ATM_VF_META, &vcc->flags);
	set_bit(ATM_VF_READY, &vcc->flags);

	/* Set default values to these variables */
	priv->maximum_unknown_frame_count = 1;
	priv->max_unknown_frame_time = (1 * HZ);
	priv->vcc_timeout_period = (1200 * HZ);
	priv->max_retry_count = 1;
	priv->aging_time = (300 * HZ);
	priv->forward_delay_time = (15 * HZ);
	priv->topology_change = 0;
	priv->arp_response_time = (1 * HZ);
	priv->flush_timeout = (4 * HZ);
	priv->path_switching_delay = (6 * HZ);

	if (dev_lec[i]->flags & IFF_UP)
		netif_start_queue(dev_lec[i]);
	__module_get(THIS_MODULE);
	return i;
}

#ifdef CONFIG_PROC_FS
static const char *lec_arp_get_status_string(unsigned char status)
{
	static const char *const lec_arp_status_string[] = {
		"ESI_UNKNOWN       ",
		"ESI_ARP_PENDING   ",
		"ESI_VC_PENDING    ",
		"<Undefined>       ",
		"ESI_FLUSH_PENDING ",
		"ESI_FORWARD_DIRECT"
	};

	if (status > ESI_FORWARD_DIRECT)
		status = 3;	/* ESI_UNDEFINED */
	return lec_arp_status_string[status];
}

static void lec_info(struct seq_file *seq, struct lec_arp_table *entry)
{
	int i;

	for (i = 0; i < ETH_ALEN; i++)
		seq_printf(seq, "%2.2x", entry->mac_addr[i] & 0xff);
	seq_printf(seq, " ");
	for (i = 0; i < ATM_ESA_LEN; i++)
		seq_printf(seq, "%2.2x", entry->atm_addr[i] & 0xff);
	seq_printf(seq, " %s %4.4x", lec_arp_get_status_string(entry->status),
		   entry->flags & 0xffff);
	if (entry->vcc)
		seq_printf(seq, "%3d %3d ", entry->vcc->vpi, entry->vcc->vci);
	else
		seq_printf(seq, "        ");
	if (entry->recv_vcc) {
		seq_printf(seq, "     %3d %3d", entry->recv_vcc->vpi,
			   entry->recv_vcc->vci);
	}
	seq_putc(seq, '\n');
}

struct lec_state {
	unsigned long flags;
	struct lec_priv *locked;
	struct hlist_node *node;
	struct net_device *dev;
	int itf;
	int arp_table;
	int misc_table;
};

static void *lec_tbl_walk(struct lec_state *state, struct hlist_head *tbl,
			  loff_t *l)
{
	struct hlist_node *e = state->node;
	struct lec_arp_table *tmp;

	if (!e)
		e = tbl->first;
	if (e == SEQ_START_TOKEN) {
		e = tbl->first;
		--*l;
	}

	tmp = container_of(e, struct lec_arp_table, next);

	hlist_for_each_entry_from(tmp, next) {
		if (--*l < 0)
			break;
	}
	state->node = e;

	return (*l < 0) ? state : NULL;
}

static void *lec_arp_walk(struct lec_state *state, loff_t *l,
			  struct lec_priv *priv)
{
	void *v = NULL;
	int p;

	for (p = state->arp_table; p < LEC_ARP_TABLE_SIZE; p++) {
		v = lec_tbl_walk(state, &priv->lec_arp_tables[p], l);
		if (v)
			break;
	}
	state->arp_table = p;
	return v;
}

static void *lec_misc_walk(struct lec_state *state, loff_t *l,
			   struct lec_priv *priv)
{
	struct hlist_head *lec_misc_tables[] = {
		&priv->lec_arp_empty_ones,
		&priv->lec_no_forward,
		&priv->mcast_fwds
	};
	void *v = NULL;
	int q;

	for (q = state->misc_table; q < ARRAY_SIZE(lec_misc_tables); q++) {
		v = lec_tbl_walk(state, lec_misc_tables[q], l);
		if (v)
			break;
	}
	state->misc_table = q;
	return v;
}

static void *lec_priv_walk(struct lec_state *state, loff_t *l,
			   struct lec_priv *priv)
{
	if (!state->locked) {
		state->locked = priv;
		spin_lock_irqsave(&priv->lec_arp_lock, state->flags);
	}
	if (!lec_arp_walk(state, l, priv) && !lec_misc_walk(state, l, priv)) {
		spin_unlock_irqrestore(&priv->lec_arp_lock, state->flags);
		state->locked = NULL;
		/* Partial state reset for the next time we get called */
		state->arp_table = state->misc_table = 0;
	}
	return state->locked;
}

static void *lec_itf_walk(struct lec_state *state, loff_t *l)
{
	struct net_device *dev;
	void *v;

	dev = state->dev ? state->dev : dev_lec[state->itf];
	v = (dev && netdev_priv(dev)) ?
		lec_priv_walk(state, l, netdev_priv(dev)) : NULL;
	if (!v && dev) {
		dev_put(dev);
		/* Partial state reset for the next time we get called */
		dev = NULL;
	}
	state->dev = dev;
	return v;
}

static void *lec_get_idx(struct lec_state *state, loff_t l)
{
	void *v = NULL;

	for (; state->itf < MAX_LEC_ITF; state->itf++) {
		v = lec_itf_walk(state, &l);
		if (v)
			break;
	}
	return v;
}

static void *lec_seq_start(struct seq_file *seq, loff_t *pos)
{
	struct lec_state *state = seq->private;

	state->itf = 0;
	state->dev = NULL;
	state->locked = NULL;
	state->arp_table = 0;
	state->misc_table = 0;
	state->node = SEQ_START_TOKEN;

	return *pos ? lec_get_idx(state, *pos) : SEQ_START_TOKEN;
}

static void lec_seq_stop(struct seq_file *seq, void *v)
{
	struct lec_state *state = seq->private;

	if (state->dev) {
		spin_unlock_irqrestore(&state->locked->lec_arp_lock,
				       state->flags);
		dev_put(state->dev);
	}
}

static void *lec_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct lec_state *state = seq->private;

	v = lec_get_idx(state, 1);
	*pos += !!PTR_ERR(v);
	return v;
}

static int lec_seq_show(struct seq_file *seq, void *v)
{
	static const char lec_banner[] =
	    "Itf  MAC          ATM destination"
	    "                          Status            Flags "
	    "VPI/VCI Recv VPI/VCI\n";

	if (v == SEQ_START_TOKEN)
		seq_puts(seq, lec_banner);
	else {
		struct lec_state *state = seq->private;
		struct net_device *dev = state->dev;
		struct lec_arp_table *entry = hlist_entry(state->node,
							  struct lec_arp_table,
							  next);

		seq_printf(seq, "%s ", dev->name);
		lec_info(seq, entry);
	}
	return 0;
}

static const struct seq_operations lec_seq_ops = {
	.start = lec_seq_start,
	.next = lec_seq_next,
	.stop = lec_seq_stop,
	.show = lec_seq_show,
};

static int lec_seq_open(struct inode *inode, struct file *file)
{