[deliverable/linux.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 <asm/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/notifier.h>
#include <linux/init.h>
#include <net/ip.h>
#include <net/route.h>
#include <linux/skbuff.h>
#include <linux/moduleparam.h>
#include <net/sock.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|IFF_BROADCAST)

/* "teql*" qdisc routines */

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

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

	__skb_unlink(skb, &q->q);
	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 sk_buff *skb;

	skb = __skb_dequeue(&dat->q);
	if (skb == NULL) {
		struct net_device *m = dat->m->dev->qdisc->dev;
		if (m) {
			dat->m->slaves = sch;
			netif_wake_queue(m);
		}
	}
	sch->q.qlen = dat->q.qlen + dat->m->dev->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) {
						master->slaves = NULL;
						spin_lock_bh(&master->dev->queue_lock);
						qdisc_reset(master->dev->qdisc);
						spin_unlock_bh(&master->dev->queue_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 rtattr *opt)
{
	struct net_device *dev = sch->dev;
	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;
}

/* "teql*" netdevice routines */

static int
__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev)
{
	struct teql_sched_data *q = qdisc_priv(dev->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)
{
	if (dev->hard_header == 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;
	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 = q->dev;
		
		if (slave->qdisc_sleeping != q)
			continue;
		if (netif_queue_stopped(slave) || ! netif_running(slave)) {
			busy = 1;
			continue;
		}

		switch (teql_resolve(skb, skb_res, slave)) {
		case 0:
			if (netif_tx_trylock(slave)) {
				if (!netif_queue_stopped(slave) &&
				    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->nh.raw - skb->data);
	} 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 = q->dev;

		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 > q->dev->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;
	SET_MODULE_OWNER(dev);
}

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>
	12	#include <asm/uaccess.h>
	13	#include <asm/system.h>
	14	#include <linux/bitops.h>
	15	#include <linux/types.h>
	16	#include <linux/kernel.h>
	17	#include <linux/sched.h>
	18	#include <linux/string.h>
	19	#include <linux/mm.h>
	20	#include <linux/socket.h>
	21	#include <linux/sockios.h>
	22	#include <linux/in.h>
	23	#include <linux/errno.h>
	24	#include <linux/interrupt.h>
14c85021	25	#include <linux/if_arp.h>
1da177e4 LT	26	#include <linux/if_ether.h>
	27	#include <linux/inet.h>
	28	#include <linux/netdevice.h>
	29	#include <linux/etherdevice.h>
	30	#include <linux/notifier.h>
	31	#include <linux/init.h>
	32	#include <net/ip.h>
	33	#include <net/route.h>
	34	#include <linux/skbuff.h>
	35	#include <linux/moduleparam.h>
	36	#include <net/sock.h>
	37	#include <net/pkt_sched.h>
	38
	39	/*
	40	How to setup it.
	41	----------------
	42
	43	After loading this module you will find a new device teqlN
	44	and new qdisc with the same name. To join a slave to the equalizer
	45	you should just set this qdisc on a device f.e.
	46
	47	# tc qdisc add dev eth0 root teql0
	48	# tc qdisc add dev eth1 root teql0
	49
	50	That's all. Full PnP 8)
	51
	52	Applicability.
	53	--------------
	54
	55	1. Slave devices MUST be active devices, i.e., they must raise the tbusy
	56	signal and generate EOI events. If you want to equalize virtual devices
	57	like tunnels, use a normal eql device.
	58	2. This device puts no limitations on physical slave characteristics
	59	f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
	60	Certainly, large difference in link speeds will make the resulting
	61	eqalized link unusable, because of huge packet reordering.
	62	I estimate an upper useful difference as ~10 times.
	63	3. If the slave requires address resolution, only protocols using
	64	neighbour cache (IPv4/IPv6) will work over the equalized link.
	65	Other protocols are still allowed to use the slave device directly,
	66	which will not break load balancing, though native slave
	67	traffic will have the highest priority. */
	68
	69	struct teql_master
	70	{
	71	struct Qdisc_ops qops;
	72	struct net_device *dev;
	73	struct Qdisc *slaves;
	74	struct list_head master_list;
	75	struct net_device_stats stats;
	76	};
	77
	78	struct teql_sched_data
	79	{
	80	struct Qdisc *next;
	81	struct teql_master *m;
	82	struct neighbour *ncache;
	83	struct sk_buff_head q;
	84	};
	85
	86	#define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next)
	87
	88	#define FMASK (IFF_BROADCAST\|IFF_POINTOPOINT\|IFF_BROADCAST)
	89
90	/* "teql" qdisc routines /
91
92	static int
93	teql_enqueue(struct sk_buff skb, struct Qdisc sch)
94	{
95	struct net_device *dev = sch->dev;
96	struct teql_sched_data *q = qdisc_priv(sch);
97
98	__skb_queue_tail(&q->q, skb);
99	if (q->q.qlen <= dev->tx_queue_len) {
100	sch->bstats.bytes += skb->len;
101	sch->bstats.packets++;
102	return 0;
103	}
104
105	__skb_unlink(skb, &q->q);
106	kfree_skb(skb);
107	sch->qstats.drops++;
108	return NET_XMIT_DROP;
109	}
110
111	static int
112	teql_requeue(struct sk_buff skb, struct Qdisc sch)
113	{
114	struct teql_sched_data *q = qdisc_priv(sch);
115
116	__skb_queue_head(&q->q, skb);
117	sch->qstats.requeues++;
118	return 0;
119	}
120
121	static struct sk_buff *
122	teql_dequeue(struct Qdisc* sch)
123	{
124	struct teql_sched_data *dat = qdisc_priv(sch);
125	struct sk_buff *skb;
126
127	skb = __skb_dequeue(&dat->q);
128	if (skb == NULL) {
129	struct net_device *m = dat->m->dev->qdisc->dev;
130	if (m) {
131	dat->m->slaves = sch;
132	netif_wake_queue(m);
133	}
134	}
135	sch->q.qlen = dat->q.qlen + dat->m->dev->qdisc->q.qlen;
136	return skb;
137	}
138
139	static __inline__ void
140	teql_neigh_release(struct neighbour *n)
141	{
142	if (n)
143	neigh_release(n);
144	}
145
146	static void
147	teql_reset(struct Qdisc* sch)
148	{
149	struct teql_sched_data *dat = qdisc_priv(sch);
150
151	skb_queue_purge(&dat->q);
152	sch->q.qlen = 0;
153	teql_neigh_release(xchg(&dat->ncache, NULL));
154	}
155
156	static void
157	teql_destroy(struct Qdisc* sch)
158	{
159	struct Qdisc q, prev;
160	struct teql_sched_data *dat = qdisc_priv(sch);
161	struct teql_master *master = dat->m;
162
163	if ((prev = master->slaves) != NULL) {
164	do {
165	q = NEXT_SLAVE(prev);
166	if (q == sch) {
167	NEXT_SLAVE(prev) = NEXT_SLAVE(q);
168	if (q == master->slaves) {
169	master->slaves = NEXT_SLAVE(q);
170	if (q == master->slaves) {
171	master->slaves = NULL;
172	spin_lock_bh(&master->dev->queue_lock);
173	qdisc_reset(master->dev->qdisc);
174	spin_unlock_bh(&master->dev->queue_lock);
175	}
176	}
177	skb_queue_purge(&dat->q);
178	teql_neigh_release(xchg(&dat->ncache, NULL));
179	break;
180	}
181
182	} while ((prev = q) != master->slaves);
183	}
184	}
185
186	static int teql_qdisc_init(struct Qdisc sch, struct rtattr opt)
187	{
188	struct net_device *dev = sch->dev;
189	struct teql_master m = (struct teql_master)sch->ops;
190	struct teql_sched_data *q = qdisc_priv(sch);
191
192	if (dev->hard_header_len > m->dev->hard_header_len)
193	return -EINVAL;
194
195	if (m->dev == dev)
196	return -ELOOP;
197
198	q->m = m;
199
200	skb_queue_head_init(&q->q);
201
202	if (m->slaves) {
203	if (m->dev->flags & IFF_UP) {
204	if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT))
205	\|\| (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST))
206	\|\| (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST))
207	\|\| dev->mtu < m->dev->mtu)
208	return -EINVAL;
209	} else {
210	if (!(dev->flags&IFF_POINTOPOINT))
211	m->dev->flags &= ~IFF_POINTOPOINT;
212	if (!(dev->flags&IFF_BROADCAST))
213	m->dev->flags &= ~IFF_BROADCAST;
214	if (!(dev->flags&IFF_MULTICAST))
215	m->dev->flags &= ~IFF_MULTICAST;
216	if (dev->mtu < m->dev->mtu)
217	m->dev->mtu = dev->mtu;
218	}
219	q->next = NEXT_SLAVE(m->slaves);
220	NEXT_SLAVE(m->slaves) = sch;
221	} else {
222	q->next = sch;
223	m->slaves = sch;
224	m->dev->mtu = dev->mtu;
225	m->dev->flags = (m->dev->flags&~FMASK)\|(dev->flags&FMASK);
226	}
227	return 0;
228	}
229
230	/* "teql" netdevice routines /
231
232	static int
233	__teql_resolve(struct sk_buff skb, struct sk_buff skb_res, struct net_device *dev)
234	{
235	struct teql_sched_data *q = qdisc_priv(dev->qdisc);
236	struct neighbour *mn = skb->dst->neighbour;
237	struct neighbour *n = q->ncache;
238
239	if (mn->tbl == NULL)
240	return -EINVAL;
241	if (n && n->tbl == mn->tbl &&
242	memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
243	atomic_inc(&n->refcnt);
244	} else {
245	n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
246	if (IS_ERR(n))
247	return PTR_ERR(n);
248	}
249	if (neigh_event_send(n, skb_res) == 0) {
250	int err;
251	read_lock(&n->lock);
252	err = dev->hard_header(skb, dev, ntohs(skb->protocol), n->ha, NULL, skb->len);
253	read_unlock(&n->lock);
254	if (err < 0) {
255	neigh_release(n);
256	return -EINVAL;
257	}
258	teql_neigh_release(xchg(&q->ncache, n));
259	return 0;
260	}
261	neigh_release(n);
262	return (skb_res == NULL) ? -EAGAIN : 1;
263	}
264
265	static __inline__ int
266	teql_resolve(struct sk_buff skb, struct sk_buff skb_res, struct net_device *dev)
267	{
268	if (dev->hard_header == NULL \|\|
269	skb->dst == NULL \|\|
270	skb->dst->neighbour == NULL)
271	return 0;
272	return __teql_resolve(skb, skb_res, dev);
273	}
274
275	static int teql_master_xmit(struct sk_buff skb, struct net_device dev)
276	{
2941a486	277	struct teql_master *master = netdev_priv(dev);
1da177e4 LT	278	struct Qdisc start, q;
	279	int busy;
	280	int nores;
	281	int len = skb->len;
	282	struct sk_buff *skb_res = NULL;
	283
	284	start = master->slaves;
	285
	286	restart:
	287	nores = 0;
	288	busy = 0;
	289
	290	if ((q = start) == NULL)
	291	goto drop;
	292
	293	do {
	294	struct net_device *slave = q->dev;
	295
	296	if (slave->qdisc_sleeping != q)
	297	continue;
	298	if (netif_queue_stopped(slave) \|\| ! netif_running(slave)) {
	299	busy = 1;
	300	continue;
	301	}
	302
	303	switch (teql_resolve(skb, skb_res, slave)) {
	304	case 0:
932ff279	305	if (netif_tx_trylock(slave)) {
1da177e4 LT	306	if (!netif_queue_stopped(slave) &&
1da177e4 LT	307	slave->hard_start_xmit(skb, slave) == 0) {
932ff279	308	netif_tx_unlock(slave);
1da177e4 LT	309	master->slaves = NEXT_SLAVE(q);
	310	netif_wake_queue(dev);
	311	master->stats.tx_packets++;
	312	master->stats.tx_bytes += len;
	313	return 0;
	314	}
932ff279	315	netif_tx_unlock(slave);
1da177e4 LT	316	}
	317	if (netif_queue_stopped(dev))
	318	busy = 1;
	319	break;
	320	case 1:
	321	master->slaves = NEXT_SLAVE(q);
	322	return 0;
	323	default:
	324	nores = 1;
	325	break;
	326	}
	327	__skb_pull(skb, skb->nh.raw - skb->data);
	328	} while ((q = NEXT_SLAVE(q)) != start);
	329
	330	if (nores && skb_res == NULL) {
	331	skb_res = skb;
	332	goto restart;
	333	}
	334
	335	if (busy) {
	336	netif_stop_queue(dev);
	337	return 1;
	338	}
	339	master->stats.tx_errors++;
	340
	341	drop:
	342	master->stats.tx_dropped++;
	343	dev_kfree_skb(skb);
	344	return 0;
	345	}
	346
	347	static int teql_master_open(struct net_device *dev)
	348	{
	349	struct Qdisc * q;
2941a486	350	struct teql_master *m = netdev_priv(dev);
1da177e4 LT	351	int mtu = 0xFFFE;
	352	unsigned flags = IFF_NOARP\|IFF_MULTICAST;
	353
	354	if (m->slaves == NULL)
	355	return -EUNATCH;
	356
	357	flags = FMASK;
	358
	359	q = m->slaves;
	360	do {
	361	struct net_device *slave = q->dev;
	362
	363	if (slave == NULL)
	364	return -EUNATCH;
	365
	366	if (slave->mtu < mtu)
	367	mtu = slave->mtu;
	368	if (slave->hard_header_len > LL_MAX_HEADER)
	369	return -EINVAL;
	370
	371	/* If all the slaves are BROADCAST, master is BROADCAST
	372	If all the slaves are PtP, master is PtP
	373	Otherwise, master is NBMA.
	374	*/
	375	if (!(slave->flags&IFF_POINTOPOINT))
	376	flags &= ~IFF_POINTOPOINT;
	377	if (!(slave->flags&IFF_BROADCAST))
	378	flags &= ~IFF_BROADCAST;
	379	if (!(slave->flags&IFF_MULTICAST))
	380	flags &= ~IFF_MULTICAST;
	381	} while ((q = NEXT_SLAVE(q)) != m->slaves);
	382
	383	m->dev->mtu = mtu;
	384	m->dev->flags = (m->dev->flags&~FMASK) \| flags;
	385	netif_start_queue(m->dev);
	386	return 0;
	387	}
	388
	389	static int teql_master_close(struct net_device *dev)
	390	{
	391	netif_stop_queue(dev);
	392	return 0;
	393	}
	394
	395	static struct net_device_stats teql_master_stats(struct net_device dev)
	396	{
2941a486	397	struct teql_master *m = netdev_priv(dev);
1da177e4 LT	398	return &m->stats;
	399	}
	400
	401	static int teql_master_mtu(struct net_device *dev, int new_mtu)
	402	{
2941a486	403	struct teql_master *m = netdev_priv(dev);
1da177e4 LT	404	struct Qdisc *q;
	405
	406	if (new_mtu < 68)
	407	return -EINVAL;
	408
	409	q = m->slaves;
	410	if (q) {
	411	do {
	412	if (new_mtu > q->dev->mtu)
	413	return -EINVAL;
	414	} while ((q=NEXT_SLAVE(q)) != m->slaves);
	415	}
	416
	417	dev->mtu = new_mtu;
	418	return 0;
	419	}
	420
	421	static __init void teql_master_setup(struct net_device *dev)
	422	{
2941a486	423	struct teql_master *master = netdev_priv(dev);
1da177e4 LT	424	struct Qdisc_ops *ops = &master->qops;
	425
	426	master->dev = dev;
	427	ops->priv_size = sizeof(struct teql_sched_data);
	428
	429	ops->enqueue = teql_enqueue;
	430	ops->dequeue = teql_dequeue;
	431	ops->requeue = teql_requeue;
	432	ops->init = teql_qdisc_init;
	433	ops->reset = teql_reset;
	434	ops->destroy = teql_destroy;
	435	ops->owner = THIS_MODULE;
	436
	437	dev->open = teql_master_open;
	438	dev->hard_start_xmit = teql_master_xmit;
	439	dev->stop = teql_master_close;
	440	dev->get_stats = teql_master_stats;
	441	dev->change_mtu = teql_master_mtu;
	442	dev->type = ARPHRD_VOID;
	443	dev->mtu = 1500;
	444	dev->tx_queue_len = 100;
	445	dev->flags = IFF_NOARP;
	446	dev->hard_header_len = LL_MAX_HEADER;
	447	SET_MODULE_OWNER(dev);
	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
	492	static void __exit teql_exit(void)
	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");