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_reset(struct Qdisc *sch)
128 struct teql_sched_data *dat = qdisc_priv(sch);
130 skb_queue_purge(&dat->q);
135 teql_destroy(struct Qdisc *sch)
137 struct Qdisc *q, *prev;
138 struct teql_sched_data *dat = qdisc_priv(sch);
139 struct teql_master *master = dat->m;
144 prev = master->slaves;
147 q = NEXT_SLAVE(prev);
149 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
150 if (q == master->slaves) {
151 master->slaves = NEXT_SLAVE(q);
152 if (q == master->slaves) {
153 struct netdev_queue *txq;
154 spinlock_t *root_lock;
156 txq = netdev_get_tx_queue(master->dev, 0);
157 master->slaves = NULL;
159 root_lock = qdisc_root_sleeping_lock(rtnl_dereference(txq->qdisc));
160 spin_lock_bh(root_lock);
161 qdisc_reset(rtnl_dereference(txq->qdisc));
162 spin_unlock_bh(root_lock);
165 skb_queue_purge(&dat->q);
169 } while ((prev = q) != master->slaves);
173 static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
175 struct net_device *dev = qdisc_dev(sch);
176 struct teql_master *m = (struct teql_master *)sch->ops;
177 struct teql_sched_data *q = qdisc_priv(sch);
179 if (dev->hard_header_len > m->dev->hard_header_len)
187 skb_queue_head_init(&q->q);
190 if (m->dev->flags & IFF_UP) {
191 if ((m->dev->flags & IFF_POINTOPOINT &&
192 !(dev->flags & IFF_POINTOPOINT)) ||
193 (m->dev->flags & IFF_BROADCAST &&
194 !(dev->flags & IFF_BROADCAST)) ||
195 (m->dev->flags & IFF_MULTICAST &&
196 !(dev->flags & IFF_MULTICAST)) ||
197 dev->mtu < m->dev->mtu)
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;
209 q->next = NEXT_SLAVE(m->slaves);
210 NEXT_SLAVE(m->slaves) = sch;
214 m->dev->mtu = dev->mtu;
215 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
222 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res,
223 struct net_device *dev, struct netdev_queue *txq,
224 struct dst_entry *dst)
229 n = dst_neigh_lookup_skb(dst, skb);
233 if (dst->dev != dev) {
234 struct neighbour *mn;
236 mn = __neigh_lookup_errno(n->tbl, n->primary_key, dev);
243 if (neigh_event_send(n, skb_res) == 0) {
245 char haddr[MAX_ADDR_LEN];
247 neigh_ha_snapshot(haddr, n, dev);
248 err = dev_hard_header(skb, dev, ntohs(tc_skb_protocol(skb)),
249 haddr, NULL, skb->len);
254 err = (skb_res == NULL) ? -EAGAIN : 1;
260 static inline int teql_resolve(struct sk_buff *skb,
261 struct sk_buff *skb_res,
262 struct net_device *dev,
263 struct netdev_queue *txq)
265 struct dst_entry *dst = skb_dst(skb);
268 if (rcu_access_pointer(txq->qdisc) == &noop_qdisc)
271 if (!dev->header_ops || !dst)
275 res = __teql_resolve(skb, skb_res, dev, txq, dst);
281 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
283 struct teql_master *master = netdev_priv(dev);
284 struct Qdisc *start, *q;
287 int subq = skb_get_queue_mapping(skb);
288 struct sk_buff *skb_res = NULL;
290 start = master->slaves;
301 struct net_device *slave = qdisc_dev(q);
302 struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0);
304 if (slave_txq->qdisc_sleeping != q)
306 if (netif_xmit_stopped(netdev_get_tx_queue(slave, subq)) ||
307 !netif_running(slave)) {
312 switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
314 if (__netif_tx_trylock(slave_txq)) {
315 unsigned int length = qdisc_pkt_len(skb);
317 if (!netif_xmit_frozen_or_stopped(slave_txq) &&
318 netdev_start_xmit(skb, slave, slave_txq, false) ==
320 __netif_tx_unlock(slave_txq);
321 master->slaves = NEXT_SLAVE(q);
322 netif_wake_queue(dev);
323 master->tx_packets++;
324 master->tx_bytes += length;
327 __netif_tx_unlock(slave_txq);
329 if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0)))
333 master->slaves = NEXT_SLAVE(q);
339 __skb_pull(skb, skb_network_offset(skb));
340 } while ((q = NEXT_SLAVE(q)) != start);
342 if (nores && skb_res == NULL) {
348 netif_stop_queue(dev);
349 return NETDEV_TX_BUSY;
354 master->tx_dropped++;
359 static int teql_master_open(struct net_device *dev)
362 struct teql_master *m = netdev_priv(dev);
364 unsigned int flags = IFF_NOARP | IFF_MULTICAST;
366 if (m->slaves == NULL)
373 struct net_device *slave = qdisc_dev(q);
378 if (slave->mtu < mtu)
380 if (slave->hard_header_len > LL_MAX_HEADER)
383 /* If all the slaves are BROADCAST, master is BROADCAST
384 If all the slaves are PtP, master is PtP
385 Otherwise, master is NBMA.
387 if (!(slave->flags&IFF_POINTOPOINT))
388 flags &= ~IFF_POINTOPOINT;
389 if (!(slave->flags&IFF_BROADCAST))
390 flags &= ~IFF_BROADCAST;
391 if (!(slave->flags&IFF_MULTICAST))
392 flags &= ~IFF_MULTICAST;
393 } while ((q = NEXT_SLAVE(q)) != m->slaves);
396 m->dev->flags = (m->dev->flags&~FMASK) | flags;
397 netif_start_queue(m->dev);
401 static int teql_master_close(struct net_device *dev)
403 netif_stop_queue(dev);
407 static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev,
408 struct rtnl_link_stats64 *stats)
410 struct teql_master *m = netdev_priv(dev);
412 stats->tx_packets = m->tx_packets;
413 stats->tx_bytes = m->tx_bytes;
414 stats->tx_errors = m->tx_errors;
415 stats->tx_dropped = m->tx_dropped;
419 static int teql_master_mtu(struct net_device *dev, int new_mtu)
421 struct teql_master *m = netdev_priv(dev);
430 if (new_mtu > qdisc_dev(q)->mtu)
432 } while ((q = NEXT_SLAVE(q)) != m->slaves);
439 static const struct net_device_ops teql_netdev_ops = {
440 .ndo_open = teql_master_open,
441 .ndo_stop = teql_master_close,
442 .ndo_start_xmit = teql_master_xmit,
443 .ndo_get_stats64 = teql_master_stats64,
444 .ndo_change_mtu = teql_master_mtu,
447 static __init void teql_master_setup(struct net_device *dev)
449 struct teql_master *master = netdev_priv(dev);
450 struct Qdisc_ops *ops = &master->qops;
453 ops->priv_size = sizeof(struct teql_sched_data);
455 ops->enqueue = teql_enqueue;
456 ops->dequeue = teql_dequeue;
457 ops->peek = teql_peek;
458 ops->init = teql_qdisc_init;
459 ops->reset = teql_reset;
460 ops->destroy = teql_destroy;
461 ops->owner = THIS_MODULE;
463 dev->netdev_ops = &teql_netdev_ops;
464 dev->type = ARPHRD_VOID;
466 dev->tx_queue_len = 100;
467 dev->flags = IFF_NOARP;
468 dev->hard_header_len = LL_MAX_HEADER;
472 static LIST_HEAD(master_dev_list);
473 static int max_equalizers = 1;
474 module_param(max_equalizers, int, 0);
475 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
477 static int __init teql_init(void)
482 for (i = 0; i < max_equalizers; i++) {
483 struct net_device *dev;
484 struct teql_master *master;
486 dev = alloc_netdev(sizeof(struct teql_master), "teql%d",
487 NET_NAME_UNKNOWN, teql_master_setup);
493 if ((err = register_netdev(dev))) {
498 master = netdev_priv(dev);
500 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
501 err = register_qdisc(&master->qops);
504 unregister_netdev(dev);
509 list_add_tail(&master->master_list, &master_dev_list);
514 static void __exit teql_exit(void)
516 struct teql_master *master, *nxt;
518 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
520 list_del(&master->master_list);
522 unregister_qdisc(&master->qops);
523 unregister_netdev(master->dev);
524 free_netdev(master->dev);
528 module_init(teql_init);
529 module_exit(teql_exit);
531 MODULE_LICENSE("GPL");