1 /* net/sched/sch_teql.c "True" (or "trivial") link equalizer.
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.
8 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/slab.h>
15 #include <linux/string.h>
16 #include <linux/errno.h>
17 #include <linux/if_arp.h>
18 #include <linux/netdevice.h>
19 #include <linux/init.h>
20 #include <linux/skbuff.h>
21 #include <linux/moduleparam.h>
23 #include <net/neighbour.h>
24 #include <net/pkt_sched.h>
30 After loading this module you will find a new device teqlN
31 and new qdisc with the same name. To join a slave to the equalizer
32 you should just set this qdisc on a device f.e.
34 # tc qdisc add dev eth0 root teql0
35 # tc qdisc add dev eth1 root teql0
37 That's all. Full PnP 8)
42 1. Slave devices MUST be active devices, i.e., they must raise the tbusy
43 signal and generate EOI events. If you want to equalize virtual devices
44 like tunnels, use a normal eql device.
45 2. This device puts no limitations on physical slave characteristics
46 f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
47 Certainly, large difference in link speeds will make the resulting
48 eqalized link unusable, because of huge packet reordering.
49 I estimate an upper useful difference as ~10 times.
50 3. If the slave requires address resolution, only protocols using
51 neighbour cache (IPv4/IPv6) will work over the equalized link.
52 Other protocols are still allowed to use the slave device directly,
53 which will not break load balancing, though native slave
54 traffic will have the highest priority. */
57 struct Qdisc_ops qops;
58 struct net_device *dev;
60 struct list_head master_list;
61 unsigned long tx_bytes;
62 unsigned long tx_packets;
63 unsigned long tx_errors;
64 unsigned long tx_dropped;
67 struct teql_sched_data {
69 struct teql_master *m;
70 struct sk_buff_head q;
73 #define NEXT_SLAVE(q) (((struct teql_sched_data *)qdisc_priv(q))->next)
75 #define FMASK (IFF_BROADCAST | IFF_POINTOPOINT)
77 /* "teql*" qdisc routines */
80 teql_enqueue(struct sk_buff *skb, struct Qdisc *sch)
82 struct net_device *dev = qdisc_dev(sch);
83 struct teql_sched_data *q = qdisc_priv(sch);
85 if (q->q.qlen < dev->tx_queue_len) {
86 __skb_queue_tail(&q->q, skb);
87 return NET_XMIT_SUCCESS;
90 return qdisc_drop(skb, sch);
93 static struct sk_buff *
94 teql_dequeue(struct Qdisc *sch)
96 struct teql_sched_data *dat = qdisc_priv(sch);
97 struct netdev_queue *dat_queue;
101 skb = __skb_dequeue(&dat->q);
102 dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
103 q = rcu_dereference_bh(dat_queue->qdisc);
106 struct net_device *m = qdisc_dev(q);
108 dat->m->slaves = sch;
112 qdisc_bstats_update(sch, skb);
114 sch->q.qlen = dat->q.qlen + q->q.qlen;
118 static struct sk_buff *
119 teql_peek(struct Qdisc *sch)
121 /* teql is meant to be used as root qdisc */
126 teql_neigh_release(struct neighbour *n)
133 teql_reset(struct Qdisc *sch)
135 struct teql_sched_data *dat = qdisc_priv(sch);
137 skb_queue_purge(&dat->q);
142 teql_destroy(struct Qdisc *sch)
144 struct Qdisc *q, *prev;
145 struct teql_sched_data *dat = qdisc_priv(sch);
146 struct teql_master *master = dat->m;
148 prev = master->slaves;
151 q = NEXT_SLAVE(prev);
153 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
154 if (q == master->slaves) {
155 master->slaves = NEXT_SLAVE(q);
156 if (q == master->slaves) {
157 struct netdev_queue *txq;
158 spinlock_t *root_lock;
160 txq = netdev_get_tx_queue(master->dev, 0);
161 master->slaves = NULL;
163 root_lock = qdisc_root_sleeping_lock(rtnl_dereference(txq->qdisc));
164 spin_lock_bh(root_lock);
165 qdisc_reset(rtnl_dereference(txq->qdisc));
166 spin_unlock_bh(root_lock);
169 skb_queue_purge(&dat->q);
173 } while ((prev = q) != master->slaves);
177 static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
179 struct net_device *dev = qdisc_dev(sch);
180 struct teql_master *m = (struct teql_master *)sch->ops;
181 struct teql_sched_data *q = qdisc_priv(sch);
183 if (dev->hard_header_len > m->dev->hard_header_len)
191 skb_queue_head_init(&q->q);
194 if (m->dev->flags & IFF_UP) {
195 if ((m->dev->flags & IFF_POINTOPOINT &&
196 !(dev->flags & IFF_POINTOPOINT)) ||
197 (m->dev->flags & IFF_BROADCAST &&
198 !(dev->flags & IFF_BROADCAST)) ||
199 (m->dev->flags & IFF_MULTICAST &&
200 !(dev->flags & IFF_MULTICAST)) ||
201 dev->mtu < m->dev->mtu)
204 if (!(dev->flags&IFF_POINTOPOINT))
205 m->dev->flags &= ~IFF_POINTOPOINT;
206 if (!(dev->flags&IFF_BROADCAST))
207 m->dev->flags &= ~IFF_BROADCAST;
208 if (!(dev->flags&IFF_MULTICAST))
209 m->dev->flags &= ~IFF_MULTICAST;
210 if (dev->mtu < m->dev->mtu)
211 m->dev->mtu = dev->mtu;
213 q->next = NEXT_SLAVE(m->slaves);
214 NEXT_SLAVE(m->slaves) = sch;
218 m->dev->mtu = dev->mtu;
219 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
226 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res,
227 struct net_device *dev, struct netdev_queue *txq,
228 struct dst_entry *dst)
233 n = dst_neigh_lookup_skb(dst, skb);
237 if (dst->dev != dev) {
238 struct neighbour *mn;
240 mn = __neigh_lookup_errno(n->tbl, n->primary_key, dev);
247 if (neigh_event_send(n, skb_res) == 0) {
249 char haddr[MAX_ADDR_LEN];
251 neigh_ha_snapshot(haddr, n, dev);
252 err = dev_hard_header(skb, dev, ntohs(skb->protocol), haddr,
258 err = (skb_res == NULL) ? -EAGAIN : 1;
264 static inline int teql_resolve(struct sk_buff *skb,
265 struct sk_buff *skb_res,
266 struct net_device *dev,
267 struct netdev_queue *txq)
269 struct dst_entry *dst = skb_dst(skb);
272 if (rcu_access_pointer(txq->qdisc) == &noop_qdisc)
275 if (!dev->header_ops || !dst)
279 res = __teql_resolve(skb, skb_res, dev, txq, dst);
285 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
287 struct teql_master *master = netdev_priv(dev);
288 struct Qdisc *start, *q;
291 int subq = skb_get_queue_mapping(skb);
292 struct sk_buff *skb_res = NULL;
294 start = master->slaves;
305 struct net_device *slave = qdisc_dev(q);
306 struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0);
308 if (slave_txq->qdisc_sleeping != q)
310 if (netif_xmit_stopped(netdev_get_tx_queue(slave, subq)) ||
311 !netif_running(slave)) {
316 switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
318 if (__netif_tx_trylock(slave_txq)) {
319 unsigned int length = qdisc_pkt_len(skb);
321 if (!netif_xmit_frozen_or_stopped(slave_txq) &&
322 netdev_start_xmit(skb, slave, slave_txq, false) ==
324 __netif_tx_unlock(slave_txq);
325 master->slaves = NEXT_SLAVE(q);
326 netif_wake_queue(dev);
327 master->tx_packets++;
328 master->tx_bytes += length;
331 __netif_tx_unlock(slave_txq);
333 if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0)))
337 master->slaves = NEXT_SLAVE(q);
343 __skb_pull(skb, skb_network_offset(skb));
344 } while ((q = NEXT_SLAVE(q)) != start);
346 if (nores && skb_res == NULL) {
352 netif_stop_queue(dev);
353 return NETDEV_TX_BUSY;
358 master->tx_dropped++;
363 static int teql_master_open(struct net_device *dev)
366 struct teql_master *m = netdev_priv(dev);
368 unsigned int flags = IFF_NOARP | IFF_MULTICAST;
370 if (m->slaves == NULL)
377 struct net_device *slave = qdisc_dev(q);
382 if (slave->mtu < mtu)
384 if (slave->hard_header_len > LL_MAX_HEADER)
387 /* If all the slaves are BROADCAST, master is BROADCAST
388 If all the slaves are PtP, master is PtP
389 Otherwise, master is NBMA.
391 if (!(slave->flags&IFF_POINTOPOINT))
392 flags &= ~IFF_POINTOPOINT;
393 if (!(slave->flags&IFF_BROADCAST))
394 flags &= ~IFF_BROADCAST;
395 if (!(slave->flags&IFF_MULTICAST))
396 flags &= ~IFF_MULTICAST;
397 } while ((q = NEXT_SLAVE(q)) != m->slaves);
400 m->dev->flags = (m->dev->flags&~FMASK) | flags;
401 netif_start_queue(m->dev);
405 static int teql_master_close(struct net_device *dev)
407 netif_stop_queue(dev);
411 static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev,
412 struct rtnl_link_stats64 *stats)
414 struct teql_master *m = netdev_priv(dev);
416 stats->tx_packets = m->tx_packets;
417 stats->tx_bytes = m->tx_bytes;
418 stats->tx_errors = m->tx_errors;
419 stats->tx_dropped = m->tx_dropped;
423 static int teql_master_mtu(struct net_device *dev, int new_mtu)
425 struct teql_master *m = netdev_priv(dev);
434 if (new_mtu > qdisc_dev(q)->mtu)
436 } while ((q = NEXT_SLAVE(q)) != m->slaves);
443 static const struct net_device_ops teql_netdev_ops = {
444 .ndo_open = teql_master_open,
445 .ndo_stop = teql_master_close,
446 .ndo_start_xmit = teql_master_xmit,
447 .ndo_get_stats64 = teql_master_stats64,
448 .ndo_change_mtu = teql_master_mtu,
451 static __init void teql_master_setup(struct net_device *dev)
453 struct teql_master *master = netdev_priv(dev);
454 struct Qdisc_ops *ops = &master->qops;
457 ops->priv_size = sizeof(struct teql_sched_data);
459 ops->enqueue = teql_enqueue;
460 ops->dequeue = teql_dequeue;
461 ops->peek = teql_peek;
462 ops->init = teql_qdisc_init;
463 ops->reset = teql_reset;
464 ops->destroy = teql_destroy;
465 ops->owner = THIS_MODULE;
467 dev->netdev_ops = &teql_netdev_ops;
468 dev->type = ARPHRD_VOID;
470 dev->tx_queue_len = 100;
471 dev->flags = IFF_NOARP;
472 dev->hard_header_len = LL_MAX_HEADER;
476 static LIST_HEAD(master_dev_list);
477 static int max_equalizers = 1;
478 module_param(max_equalizers, int, 0);
479 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
481 static int __init teql_init(void)
486 for (i = 0; i < max_equalizers; i++) {
487 struct net_device *dev;
488 struct teql_master *master;
490 dev = alloc_netdev(sizeof(struct teql_master), "teql%d",
491 NET_NAME_UNKNOWN, teql_master_setup);
497 if ((err = register_netdev(dev))) {
502 master = netdev_priv(dev);
504 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
505 err = register_qdisc(&master->qops);
508 unregister_netdev(dev);
513 list_add_tail(&master->master_list, &master_dev_list);
518 static void __exit teql_exit(void)
520 struct teql_master *master, *nxt;
522 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
524 list_del(&master->master_list);
526 unregister_qdisc(&master->qops);
527 unregister_netdev(master->dev);
528 free_netdev(master->dev);
532 module_init(teql_init);
533 module_exit(teql_exit);
535 MODULE_LICENSE("GPL");