[net-next-2.6.git] / net / sched / sch_teql.c

/* net/sched/sch_teql.c	"True" (or "trivial") link equalizer.
 *
 *		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.
 *
 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/if_arp.h>
#include <linux/netdevice.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/moduleparam.h>
#include <net/dst.h>
#include <net/neighbour.h>
#include <net/pkt_sched.h>

/*
   How to setup it.
   ----------------

   After loading this module you will find a new device teqlN
   and new qdisc with the same name. To join a slave to the equalizer
   you should just set this qdisc on a device f.e.

   # tc qdisc add dev eth0 root teql0
   # tc qdisc add dev eth1 root teql0

   That's all. Full PnP 8)

   Applicability.
   --------------

   1. Slave devices MUST be active devices, i.e., they must raise the tbusy
      signal and generate EOI events. If you want to equalize virtual devices
      like tunnels, use a normal eql device.
   2. This device puts no limitations on physical slave characteristics
      f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
      Certainly, large difference in link speeds will make the resulting
      eqalized link unusable, because of huge packet reordering.
      I estimate an upper useful difference as ~10 times.
   3. If the slave requires address resolution, only protocols using
      neighbour cache (IPv4/IPv6) will work over the equalized link.
      Other protocols are still allowed to use the slave device directly,
      which will not break load balancing, though native slave
      traffic will have the highest priority.  */

struct teql_master
{
	struct Qdisc_ops qops;
	struct net_device *dev;
	struct Qdisc *slaves;
	struct list_head master_list;
	struct net_device_stats stats;
};

struct teql_sched_data
{
	struct Qdisc *next;
	struct teql_master *m;
	struct neighbour *ncache;
	struct sk_buff_head q;
};

#define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next)

#define FMASK (IFF_BROADCAST|IFF_POINTOPOINT)

/* "teql*" qdisc routines */

static int
teql_enqueue(struct sk_buff *skb, struct Qdisc* sch)
{
	struct net_device *dev = qdisc_dev(sch);
	struct teql_sched_data *q = qdisc_priv(sch);

	if (q->q.qlen < dev->tx_queue_len) {
		__skb_queue_tail(&q->q, skb);
		sch->bstats.bytes += skb->len;
		sch->bstats.packets++;
		return 0;
	}

	kfree_skb(skb);
	sch->qstats.drops++;
	return NET_XMIT_DROP;
}

static int
teql_requeue(struct sk_buff *skb, struct Qdisc* sch)
{
	struct teql_sched_data *q = qdisc_priv(sch);

	__skb_queue_head(&q->q, skb);
	sch->qstats.requeues++;
	return 0;
}

static struct sk_buff *
teql_dequeue(struct Qdisc* sch)
{
	struct teql_sched_data *dat = qdisc_priv(sch);
	struct netdev_queue *dat_queue;
	struct sk_buff *skb;

	skb = __skb_dequeue(&dat->q);
	dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
	if (skb == NULL) {
		struct net_device *m = qdisc_dev(dat_queue->qdisc);
		if (m) {
			dat->m->slaves = sch;
			netif_wake_queue(m);
		}
	}
	sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
	return skb;
}

static __inline__ void
teql_neigh_release(struct neighbour *n)
{
	if (n)
		neigh_release(n);
}

static void
teql_reset(struct Qdisc* sch)
{
	struct teql_sched_data *dat = qdisc_priv(sch);

	skb_queue_purge(&dat->q);
	sch->q.qlen = 0;
	teql_neigh_release(xchg(&dat->ncache, NULL));
}

static void
teql_destroy(struct Qdisc* sch)
{
	struct Qdisc *q, *prev;
	struct teql_sched_data *dat = qdisc_priv(sch);
	struct teql_master *master = dat->m;

	if ((prev = master->slaves) != NULL) {
		do {
			q = NEXT_SLAVE(prev);
			if (q == sch) {
				NEXT_SLAVE(prev) = NEXT_SLAVE(q);
				if (q == master->slaves) {
					master->slaves = NEXT_SLAVE(q);
					if (q == master->slaves) {
						struct netdev_queue *txq;

						txq = netdev_get_tx_queue(master->dev, 0);
						master->slaves = NULL;
						spin_lock_bh(&txq->lock);
						qdisc_reset(txq->qdisc);
						spin_unlock_bh(&txq->lock);
					}
				}
				skb_queue_purge(&dat->q);
				teql_neigh_release(xchg(&dat->ncache, NULL));
				break;
			}

		} while ((prev = q) != master->slaves);
	}
}

static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
{
	struct net_device *dev = qdisc_dev(sch);
	struct teql_master *m = (struct teql_master*)sch->ops;
	struct teql_sched_data *q = qdisc_priv(sch);

	if (dev->hard_header_len > m->dev->hard_header_len)
		return -EINVAL;

	if (m->dev == dev)
		return -ELOOP;

	q->m = m;

	skb_queue_head_init(&q->q);

	if (m->slaves) {
		if (m->dev->flags & IFF_UP) {
			if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
			    || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
			    || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
			    || dev->mtu < m->dev->mtu)
				return -EINVAL;
		} else {
			if (!(dev->flags&IFF_POINTOPOINT))
				m->dev->flags &= ~IFF_POINTOPOINT;
			if (!(dev->flags&IFF_BROADCAST))
				m->dev->flags &= ~IFF_BROADCAST;
			if (!(dev->flags&IFF_MULTICAST))
				m->dev->flags &= ~IFF_MULTICAST;
			if (dev->mtu < m->dev->mtu)
				m->dev->mtu = dev->mtu;
		}
		q->next = NEXT_SLAVE(m->slaves);
		NEXT_SLAVE(m->slaves) = sch;
	} else {
		q->next = sch;
		m->slaves = sch;
		m->dev->mtu = dev->mtu;
		m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
	}
	return 0;
}


static int
__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
{
	struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
	struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
	struct neighbour *mn = skb->dst->neighbour;
	struct neighbour *n = q->ncache;

	if (mn->tbl == NULL)
		return -EINVAL;
	if (n && n->tbl == mn->tbl &&
	    memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
		atomic_inc(&n->refcnt);
	} else {
		n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
		if (IS_ERR(n))
			return PTR_ERR(n);
	}
	if (neigh_event_send(n, skb_res) == 0) {
		int err;

		read_lock(&n->lock);
		err = dev_hard_header(skb, dev, ntohs(skb->protocol),
				      n->ha, NULL, skb->len);
		read_unlock(&n->lock);

		if (err < 0) {
			neigh_release(n);
			return -EINVAL;
		}
		teql_neigh_release(xchg(&q->ncache, n));
		return 0;
	}
	neigh_release(n);
	return (skb_res == NULL) ? -EAGAIN : 1;
}

static inline int teql_resolve(struct sk_buff *skb,
			       struct sk_buff *skb_res, struct net_device *dev)
{
	struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
	if (txq->qdisc == &noop_qdisc)
		return -ENODEV;

	if (dev->header_ops == NULL ||
	    skb->dst == NULL ||
	    skb->dst->neighbour == NULL)
		return 0;
	return __teql_resolve(skb, skb_res, dev);
}

static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct teql_master *master = netdev_priv(dev);
	struct Qdisc *start, *q;
	int busy;
	int nores;
	int len = skb->len;
	int subq = skb_get_queue_mapping(skb);
	struct sk_buff *skb_res = NULL;

	start = master->slaves;

restart:
	nores = 0;
	busy = 0;

	if ((q = start) == NULL)
		goto drop;

	do {
		struct net_device *slave = qdisc_dev(q);
		struct netdev_queue *slave_txq;

		slave_txq = netdev_get_tx_queue(slave, 0);
		if (slave_txq->qdisc_sleeping != q)
			continue;
		if (__netif_subqueue_stopped(slave, subq) ||
		    !netif_running(slave)) {
			busy = 1;
			continue;
		}

		switch (teql_resolve(skb, skb_res, slave)) {
		case 0:
			if (netif_tx_trylock(slave)) {
				if (!__netif_subqueue_stopped(slave, subq) &&
				    slave->hard_start_xmit(skb, slave) == 0) {
					netif_tx_unlock(slave);
					master->slaves = NEXT_SLAVE(q);
					netif_wake_queue(dev);
					master->stats.tx_packets++;
					master->stats.tx_bytes += len;
					return 0;
				}
				netif_tx_unlock(slave);
			}
			if (netif_queue_stopped(dev))
				busy = 1;
			break;
		case 1:
			master->slaves = NEXT_SLAVE(q);
			return 0;
		default:
			nores = 1;
			break;
		}
		__skb_pull(skb, skb_network_offset(skb));
	} while ((q = NEXT_SLAVE(q)) != start);

	if (nores && skb_res == NULL) {
		skb_res = skb;
		goto restart;
	}

	if (busy) {
		netif_stop_queue(dev);
		return 1;
	}
	master->stats.tx_errors++;

drop:
	master->stats.tx_dropped++;
	dev_kfree_skb(skb);
	return 0;
}

static int teql_master_open(struct net_device *dev)
{
	struct Qdisc * q;
	struct teql_master *m = netdev_priv(dev);
	int mtu = 0xFFFE;
	unsigned flags = IFF_NOARP|IFF_MULTICAST;

	if (m->slaves == NULL)
		return -EUNATCH;

	flags = FMASK;

	q = m->slaves;
	do {
		struct net_device *slave = qdisc_dev(q);

		if (slave == NULL)
			return -EUNATCH;

		if (slave->mtu < mtu)
			mtu = slave->mtu;
		if (slave->hard_header_len > LL_MAX_HEADER)
			return -EINVAL;

		/* If all the slaves are BROADCAST, master is BROADCAST
		   If all the slaves are PtP, master is PtP
		   Otherwise, master is NBMA.
		 */
		if (!(slave->flags&IFF_POINTOPOINT))
			flags &= ~IFF_POINTOPOINT;
		if (!(slave->flags&IFF_BROADCAST))
			flags &= ~IFF_BROADCAST;
		if (!(slave->flags&IFF_MULTICAST))
			flags &= ~IFF_MULTICAST;
	} while ((q = NEXT_SLAVE(q)) != m->slaves);

	m->dev->mtu = mtu;
	m->dev->flags = (m->dev->flags&~FMASK) | flags;
	netif_start_queue(m->dev);
	return 0;
}

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

static struct net_device_stats *teql_master_stats(struct net_device *dev)
{
	struct teql_master *m = netdev_priv(dev);
	return &m->stats;
}

static int teql_master_mtu(struct net_device *dev, int new_mtu)
{
	struct teql_master *m = netdev_priv(dev);
	struct Qdisc *q;

	if (new_mtu < 68)
		return -EINVAL;

	q = m->slaves;
	if (q) {
		do {
			if (new_mtu > qdisc_dev(q)->mtu)
				return -EINVAL;
		} while ((q=NEXT_SLAVE(q)) != m->slaves);
	}

	dev->mtu = new_mtu;
	return 0;
}

static __init void teql_master_setup(struct net_device *dev)
{
	struct teql_master *master = netdev_priv(dev);
	struct Qdisc_ops *ops = &master->qops;

	master->dev	= dev;
	ops->priv_size  = sizeof(struct teql_sched_data);

	ops->enqueue	=	teql_enqueue;
	ops->dequeue	=	teql_dequeue;
	ops->requeue	=	teql_requeue;
	ops->init	=	teql_qdisc_init;
	ops->reset	=	teql_reset;
	ops->destroy	=	teql_destroy;
	ops->owner	=	THIS_MODULE;

	dev->open		= teql_master_open;
	dev->hard_start_xmit	= teql_master_xmit;
	dev->stop		= teql_master_close;
	dev->get_stats		= teql_master_stats;
	dev->change_mtu		= teql_master_mtu;
	dev->type		= ARPHRD_VOID;
	dev->mtu		= 1500;
	dev->tx_queue_len	= 100;
	dev->flags		= IFF_NOARP;
	dev->hard_header_len	= LL_MAX_HEADER;
}

static LIST_HEAD(master_dev_list);
static int max_equalizers = 1;
module_param(max_equalizers, int, 0);
MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");

static int __init teql_init(void)
{
	int i;
	int err = -ENODEV;

	for (i = 0; i < max_equalizers; i++) {
		struct net_device *dev;
		struct teql_master *master;

		dev = alloc_netdev(sizeof(struct teql_master),
				  "teql%d", teql_master_setup);
		if (!dev) {
			err = -ENOMEM;
			break;
		}

		if ((err = register_netdev(dev))) {
			free_netdev(dev);
			break;
		}

		master = netdev_priv(dev);

		strlcpy(master->qops.id, dev->name, IFNAMSIZ);
		err = register_qdisc(&master->qops);

		if (err) {
			unregister_netdev(dev);
			free_netdev(dev);
			break;
		}

		list_add_tail(&master->master_list, &master_dev_list);
	}
	return i ? 0 : err;
}

static void __exit teql_exit(void)
{
	struct teql_master *master, *nxt;

	list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {

		list_del(&master->master_list);

		unregister_qdisc(&master->qops);
		unregister_netdev(master->dev);
		free_netdev(master->dev);
	}
}

module_init(teql_init);
module_exit(teql_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
1da177e4 LT	1	/* net/sched/sch_teql.c "True" (or "trivial") link equalizer.
	2	*
	3	* This program is free software; you can redistribute it and/or
	4	* modify it under the terms of the GNU General Public License
	5	* as published by the Free Software Foundation; either version
	6	* 2 of the License, or (at your option) any later version.
	7	*
	8	* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	9	*/
	10
	11	#include <linux/module.h>
1da177e4 LT	12	#include <linux/types.h>
1da177e4 LT	13	#include <linux/kernel.h>
1da177e4	14	#include <linux/string.h>
1da177e4	15	#include <linux/errno.h>
14c85021	16	#include <linux/if_arp.h>
1da177e4	17	#include <linux/netdevice.h>
1da177e4	18	#include <linux/init.h>
1da177e4 LT	19	#include <linux/skbuff.h>
1da177e4 LT	20	#include <linux/moduleparam.h>
0ba48053 PM	21	#include <net/dst.h>
0ba48053 PM	22	#include <net/neighbour.h>
1da177e4 LT	23	#include <net/pkt_sched.h>
	24
	25	/*
	26	How to setup it.
	27	----------------
	28
	29	After loading this module you will find a new device teqlN
	30	and new qdisc with the same name. To join a slave to the equalizer
	31	you should just set this qdisc on a device f.e.
	32
	33	# tc qdisc add dev eth0 root teql0
	34	# tc qdisc add dev eth1 root teql0
	35
	36	That's all. Full PnP 8)
	37
	38	Applicability.
	39	--------------
	40
	41	1. Slave devices MUST be active devices, i.e., they must raise the tbusy
	42	signal and generate EOI events. If you want to equalize virtual devices
	43	like tunnels, use a normal eql device.
	44	2. This device puts no limitations on physical slave characteristics
	45	f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
	46	Certainly, large difference in link speeds will make the resulting
	47	eqalized link unusable, because of huge packet reordering.
	48	I estimate an upper useful difference as ~10 times.
	49	3. If the slave requires address resolution, only protocols using
	50	neighbour cache (IPv4/IPv6) will work over the equalized link.
	51	Other protocols are still allowed to use the slave device directly,
	52	which will not break load balancing, though native slave
	53	traffic will have the highest priority. */
	54
	55	struct teql_master
	56	{
	57	struct Qdisc_ops qops;
	58	struct net_device *dev;
	59	struct Qdisc *slaves;
	60	struct list_head master_list;
	61	struct net_device_stats stats;
	62	};
	63
	64	struct teql_sched_data
	65	{
	66	struct Qdisc *next;
	67	struct teql_master *m;
	68	struct neighbour *ncache;
	69	struct sk_buff_head q;
	70	};
	71
	72	#define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next)
	73
cc8fd14d	74	#define FMASK (IFF_BROADCAST\|IFF_POINTOPOINT)
1da177e4 LT	75
	76	/* "teql" qdisc routines /
	77
	78	static int
	79	teql_enqueue(struct sk_buff skb, struct Qdisc sch)
	80	{
5ce2d488	81	struct net_device *dev = qdisc_dev(sch);
1da177e4 LT	82	struct teql_sched_data *q = qdisc_priv(sch);
1da177e4 LT	83
4cd8c9e8 KK	84	if (q->q.qlen < dev->tx_queue_len) {
4cd8c9e8 KK	85	__skb_queue_tail(&q->q, skb);
1da177e4 LT	86	sch->bstats.bytes += skb->len;
	87	sch->bstats.packets++;
	88	return 0;
	89	}
	90
1da177e4 LT	91	kfree_skb(skb);
	92	sch->qstats.drops++;
	93	return NET_XMIT_DROP;
	94	}
	95
	96	static int
	97	teql_requeue(struct sk_buff skb, struct Qdisc sch)
	98	{
	99	struct teql_sched_data *q = qdisc_priv(sch);
	100
	101	__skb_queue_head(&q->q, skb);
	102	sch->qstats.requeues++;
	103	return 0;
	104	}
	105
	106	static struct sk_buff *
	107	teql_dequeue(struct Qdisc* sch)
	108	{
	109	struct teql_sched_data *dat = qdisc_priv(sch);
b0e1e646	110	struct netdev_queue *dat_queue;
1da177e4 LT	111	struct sk_buff *skb;
	112
	113	skb = __skb_dequeue(&dat->q);
e8a0464c	114	dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
1da177e4	115	if (skb == NULL) {
b0e1e646	116	struct net_device *m = qdisc_dev(dat_queue->qdisc);
1da177e4 LT	117	if (m) {
	118	dat->m->slaves = sch;
	119	netif_wake_queue(m);
	120	}
	121	}
b0e1e646	122	sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
1da177e4 LT	123	return skb;
	124	}
	125
	126	static __inline__ void
	127	teql_neigh_release(struct neighbour *n)
	128	{
	129	if (n)
	130	neigh_release(n);
	131	}
	132
	133	static void
	134	teql_reset(struct Qdisc* sch)
	135	{
	136	struct teql_sched_data *dat = qdisc_priv(sch);
	137
	138	skb_queue_purge(&dat->q);
	139	sch->q.qlen = 0;
	140	teql_neigh_release(xchg(&dat->ncache, NULL));
	141	}
	142
	143	static void
	144	teql_destroy(struct Qdisc* sch)
	145	{
	146	struct Qdisc q, prev;
	147	struct teql_sched_data *dat = qdisc_priv(sch);
	148	struct teql_master *master = dat->m;
	149
	150	if ((prev = master->slaves) != NULL) {
	151	do {
	152	q = NEXT_SLAVE(prev);
	153	if (q == sch) {
	154	NEXT_SLAVE(prev) = NEXT_SLAVE(q);
	155	if (q == master->slaves) {
	156	master->slaves = NEXT_SLAVE(q);
	157	if (q == master->slaves) {
e8a0464c DM	158	struct netdev_queue *txq;
	159
	160	txq = netdev_get_tx_queue(master->dev, 0);
1da177e4	161	master->slaves = NULL;
e8a0464c DM	162	spin_lock_bh(&txq->lock);
	163	qdisc_reset(txq->qdisc);
	164	spin_unlock_bh(&txq->lock);
1da177e4 LT	165	}
	166	}
	167	skb_queue_purge(&dat->q);
	168	teql_neigh_release(xchg(&dat->ncache, NULL));
	169	break;
	170	}
10297b99	171
1da177e4 LT	172	} while ((prev = q) != master->slaves);
	173	}
	174	}
	175
1e90474c	176	static int teql_qdisc_init(struct Qdisc sch, struct nlattr opt)
1da177e4	177	{
5ce2d488	178	struct net_device *dev = qdisc_dev(sch);
1da177e4 LT	179	struct teql_master m = (struct teql_master)sch->ops;
	180	struct teql_sched_data *q = qdisc_priv(sch);
	181
	182	if (dev->hard_header_len > m->dev->hard_header_len)
	183	return -EINVAL;
	184
	185	if (m->dev == dev)
	186	return -ELOOP;
	187
	188	q->m = m;
	189
	190	skb_queue_head_init(&q->q);
	191
	192	if (m->slaves) {
	193	if (m->dev->flags & IFF_UP) {
	194	if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
	195	\|\| (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
	196	\|\| (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
	197	\|\| dev->mtu < m->dev->mtu)
	198	return -EINVAL;
	199	} else {
	200	if (!(dev->flags&IFF_POINTOPOINT))
	201	m->dev->flags &= ~IFF_POINTOPOINT;
	202	if (!(dev->flags&IFF_BROADCAST))
	203	m->dev->flags &= ~IFF_BROADCAST;
	204	if (!(dev->flags&IFF_MULTICAST))
	205	m->dev->flags &= ~IFF_MULTICAST;
	206	if (dev->mtu < m->dev->mtu)
	207	m->dev->mtu = dev->mtu;
	208	}
	209	q->next = NEXT_SLAVE(m->slaves);
	210	NEXT_SLAVE(m->slaves) = sch;
	211	} else {
	212	q->next = sch;
	213	m->slaves = sch;
	214	m->dev->mtu = dev->mtu;
	215	m->dev->flags = (m->dev->flags&~FMASK)\|(dev->flags&FMASK);
	216	}
	217	return 0;
	218	}
	219
1da177e4 LT	220
	221	static int
	222	__teql_resolve(struct sk_buff skb, struct sk_buff skb_res, struct net_device *dev)
	223	{
e8a0464c DM	224	struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0);
e8a0464c DM	225	struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc);
1da177e4 LT	226	struct neighbour *mn = skb->dst->neighbour;
	227	struct neighbour *n = q->ncache;
	228
	229	if (mn->tbl == NULL)
	230	return -EINVAL;
	231	if (n && n->tbl == mn->tbl &&
	232	memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
	233	atomic_inc(&n->refcnt);
	234	} else {
	235	n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
	236	if (IS_ERR(n))
	237	return PTR_ERR(n);
	238	}
	239	if (neigh_event_send(n, skb_res) == 0) {
	240	int err;
0c4e8581	241
1da177e4	242	read_lock(&n->lock);
0c4e8581 SH	243	err = dev_hard_header(skb, dev, ntohs(skb->protocol),
0c4e8581 SH	244	n->ha, NULL, skb->len);
1da177e4	245	read_unlock(&n->lock);
0c4e8581	246
1da177e4 LT	247	if (err < 0) {
	248	neigh_release(n);
	249	return -EINVAL;
	250	}
	251	teql_neigh_release(xchg(&q->ncache, n));
	252	return 0;
	253	}
	254	neigh_release(n);
	255	return (skb_res == NULL) ? -EAGAIN : 1;
	256	}
	257
3b04ddde SH	258	static inline int teql_resolve(struct sk_buff *skb,
3b04ddde SH	259	struct sk_buff skb_res, struct net_device dev)
1da177e4	260	{
e8a0464c DM	261	struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
e8a0464c DM	262	if (txq->qdisc == &noop_qdisc)
4f9f8311 EP	263	return -ENODEV;
4f9f8311 EP	264
3b04ddde	265	if (dev->header_ops == NULL \|\|
1da177e4 LT	266	skb->dst == NULL \|\|
	267	skb->dst->neighbour == NULL)
	268	return 0;
	269	return __teql_resolve(skb, skb_res, dev);
	270	}
	271
	272	static int teql_master_xmit(struct sk_buff skb, struct net_device dev)
	273	{
2941a486	274	struct teql_master *master = netdev_priv(dev);
1da177e4 LT	275	struct Qdisc start, q;
	276	int busy;
	277	int nores;
	278	int len = skb->len;
4e3ab47a	279	int subq = skb_get_queue_mapping(skb);
1da177e4 LT	280	struct sk_buff *skb_res = NULL;
	281
	282	start = master->slaves;
	283
	284	restart:
	285	nores = 0;
	286	busy = 0;
	287
	288	if ((q = start) == NULL)
	289	goto drop;
	290
	291	do {
5ce2d488	292	struct net_device *slave = qdisc_dev(q);
e8a0464c	293	struct netdev_queue *slave_txq;
10297b99	294
e8a0464c DM	295	slave_txq = netdev_get_tx_queue(slave, 0);
e8a0464c DM	296	if (slave_txq->qdisc_sleeping != q)
1da177e4	297	continue;
fd2ea0a7	298	if (__netif_subqueue_stopped(slave, subq) \|\|
f25f4e44	299	!netif_running(slave)) {
1da177e4 LT	300	busy = 1;
	301	continue;
	302	}
	303
	304	switch (teql_resolve(skb, skb_res, slave)) {
	305	case 0:
932ff279	306	if (netif_tx_trylock(slave)) {
fd2ea0a7	307	if (!__netif_subqueue_stopped(slave, subq) &&
1da177e4	308	slave->hard_start_xmit(skb, slave) == 0) {
932ff279	309	netif_tx_unlock(slave);
1da177e4 LT	310	master->slaves = NEXT_SLAVE(q);
	311	netif_wake_queue(dev);
	312	master->stats.tx_packets++;
	313	master->stats.tx_bytes += len;
	314	return 0;
	315	}
932ff279	316	netif_tx_unlock(slave);
1da177e4 LT	317	}
	318	if (netif_queue_stopped(dev))
	319	busy = 1;
	320	break;
	321	case 1:
	322	master->slaves = NEXT_SLAVE(q);
	323	return 0;
	324	default:
	325	nores = 1;
	326	break;
	327	}
bbe735e4	328	__skb_pull(skb, skb_network_offset(skb));
1da177e4 LT	329	} while ((q = NEXT_SLAVE(q)) != start);
	330
	331	if (nores && skb_res == NULL) {
	332	skb_res = skb;
	333	goto restart;
	334	}
	335
	336	if (busy) {
	337	netif_stop_queue(dev);
	338	return 1;
	339	}
	340	master->stats.tx_errors++;
	341
	342	drop:
	343	master->stats.tx_dropped++;
	344	dev_kfree_skb(skb);
	345	return 0;
	346	}
	347
	348	static int teql_master_open(struct net_device *dev)
	349	{
	350	struct Qdisc * q;
2941a486	351	struct teql_master *m = netdev_priv(dev);
1da177e4 LT	352	int mtu = 0xFFFE;
	353	unsigned flags = IFF_NOARP\|IFF_MULTICAST;
	354
	355	if (m->slaves == NULL)
	356	return -EUNATCH;
	357
	358	flags = FMASK;
	359
	360	q = m->slaves;
	361	do {
5ce2d488	362	struct net_device *slave = qdisc_dev(q);
1da177e4 LT	363
	364	if (slave == NULL)
	365	return -EUNATCH;
	366
	367	if (slave->mtu < mtu)
	368	mtu = slave->mtu;
	369	if (slave->hard_header_len > LL_MAX_HEADER)
	370	return -EINVAL;
	371
	372	/* If all the slaves are BROADCAST, master is BROADCAST
	373	If all the slaves are PtP, master is PtP
	374	Otherwise, master is NBMA.
	375	*/
	376	if (!(slave->flags&IFF_POINTOPOINT))
	377	flags &= ~IFF_POINTOPOINT;
	378	if (!(slave->flags&IFF_BROADCAST))
	379	flags &= ~IFF_BROADCAST;
	380	if (!(slave->flags&IFF_MULTICAST))
	381	flags &= ~IFF_MULTICAST;
	382	} while ((q = NEXT_SLAVE(q)) != m->slaves);
	383
	384	m->dev->mtu = mtu;
	385	m->dev->flags = (m->dev->flags&~FMASK) \| flags;
	386	netif_start_queue(m->dev);
	387	return 0;
	388	}
	389
	390	static int teql_master_close(struct net_device *dev)
	391	{
	392	netif_stop_queue(dev);
	393	return 0;
	394	}
	395
	396	static struct net_device_stats teql_master_stats(struct net_device dev)
	397	{
2941a486	398	struct teql_master *m = netdev_priv(dev);
1da177e4 LT	399	return &m->stats;
	400	}
	401
	402	static int teql_master_mtu(struct net_device *dev, int new_mtu)
	403	{
2941a486	404	struct teql_master *m = netdev_priv(dev);
1da177e4 LT	405	struct Qdisc *q;
	406
	407	if (new_mtu < 68)
	408	return -EINVAL;
	409
	410	q = m->slaves;
	411	if (q) {
	412	do {
5ce2d488	413	if (new_mtu > qdisc_dev(q)->mtu)
1da177e4 LT	414	return -EINVAL;
	415	} while ((q=NEXT_SLAVE(q)) != m->slaves);
	416	}
	417
	418	dev->mtu = new_mtu;
	419	return 0;
	420	}
	421
	422	static __init void teql_master_setup(struct net_device *dev)
	423	{
2941a486	424	struct teql_master *master = netdev_priv(dev);
1da177e4 LT	425	struct Qdisc_ops *ops = &master->qops;
	426
	427	master->dev = dev;
	428	ops->priv_size = sizeof(struct teql_sched_data);
10297b99	429
1da177e4 LT	430	ops->enqueue = teql_enqueue;
	431	ops->dequeue = teql_dequeue;
	432	ops->requeue = teql_requeue;
	433	ops->init = teql_qdisc_init;
	434	ops->reset = teql_reset;
	435	ops->destroy = teql_destroy;
	436	ops->owner = THIS_MODULE;
	437
	438	dev->open = teql_master_open;
	439	dev->hard_start_xmit = teql_master_xmit;
	440	dev->stop = teql_master_close;
	441	dev->get_stats = teql_master_stats;
	442	dev->change_mtu = teql_master_mtu;
	443	dev->type = ARPHRD_VOID;
	444	dev->mtu = 1500;
	445	dev->tx_queue_len = 100;
	446	dev->flags = IFF_NOARP;
	447	dev->hard_header_len = LL_MAX_HEADER;
1da177e4 LT	448	}
	449
	450	static LIST_HEAD(master_dev_list);
	451	static int max_equalizers = 1;
	452	module_param(max_equalizers, int, 0);
	453	MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
	454
	455	static int __init teql_init(void)
	456	{
	457	int i;
	458	int err = -ENODEV;
	459
	460	for (i = 0; i < max_equalizers; i++) {
	461	struct net_device *dev;
	462	struct teql_master *master;
	463
	464	dev = alloc_netdev(sizeof(struct teql_master),
	465	"teql%d", teql_master_setup);
	466	if (!dev) {
	467	err = -ENOMEM;
	468	break;
	469	}
	470
	471	if ((err = register_netdev(dev))) {
	472	free_netdev(dev);
	473	break;
	474	}
	475
2941a486	476	master = netdev_priv(dev);
1da177e4 LT	477
	478	strlcpy(master->qops.id, dev->name, IFNAMSIZ);
	479	err = register_qdisc(&master->qops);
	480
	481	if (err) {
	482	unregister_netdev(dev);
	483	free_netdev(dev);
	484	break;
	485	}
	486
	487	list_add_tail(&master->master_list, &master_dev_list);
	488	}
	489	return i ? 0 : err;
	490	}
	491
10297b99	492	static void __exit teql_exit(void)
1da177e4 LT	493	{
	494	struct teql_master master, nxt;
	495
	496	list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
	497
	498	list_del(&master->master_list);
	499
	500	unregister_qdisc(&master->qops);
	501	unregister_netdev(master->dev);
	502	free_netdev(master->dev);
	503	}
	504	}
	505
	506	module_init(teql_init);
	507	module_exit(teql_exit);
	508
	509	MODULE_LICENSE("GPL");