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net: Add ops->ndo_xmit_flush()
[deliverable/linux.git] / net / sched / sch_teql.c
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 <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>
22 #include <net/dst.h>
23 #include <net/neighbour.h>
24 #include <net/pkt_sched.h>
25
26 /*
27 How to setup it.
28 ----------------
29
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.
33
34 # tc qdisc add dev eth0 root teql0
35 # tc qdisc add dev eth1 root teql0
36
37 That's all. Full PnP 8)
38
39 Applicability.
40 --------------
41
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. */
55
56 struct teql_master {
57 struct Qdisc_ops qops;
58 struct net_device *dev;
59 struct Qdisc *slaves;
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;
65 };
66
67 struct teql_sched_data {
68 struct Qdisc *next;
69 struct teql_master *m;
70 struct sk_buff_head q;
71 };
72
73 #define NEXT_SLAVE(q) (((struct teql_sched_data *)qdisc_priv(q))->next)
74
75 #define FMASK (IFF_BROADCAST | IFF_POINTOPOINT)
76
77 /* "teql*" qdisc routines */
78
79 static int
80 teql_enqueue(struct sk_buff *skb, struct Qdisc *sch)
81 {
82 struct net_device *dev = qdisc_dev(sch);
83 struct teql_sched_data *q = qdisc_priv(sch);
84
85 if (q->q.qlen < dev->tx_queue_len) {
86 __skb_queue_tail(&q->q, skb);
87 return NET_XMIT_SUCCESS;
88 }
89
90 return qdisc_drop(skb, sch);
91 }
92
93 static struct sk_buff *
94 teql_dequeue(struct Qdisc *sch)
95 {
96 struct teql_sched_data *dat = qdisc_priv(sch);
97 struct netdev_queue *dat_queue;
98 struct sk_buff *skb;
99
100 skb = __skb_dequeue(&dat->q);
101 dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
102 if (skb == NULL) {
103 struct net_device *m = qdisc_dev(dat_queue->qdisc);
104 if (m) {
105 dat->m->slaves = sch;
106 netif_wake_queue(m);
107 }
108 } else {
109 qdisc_bstats_update(sch, skb);
110 }
111 sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
112 return skb;
113 }
114
115 static struct sk_buff *
116 teql_peek(struct Qdisc *sch)
117 {
118 /* teql is meant to be used as root qdisc */
119 return NULL;
120 }
121
122 static inline void
123 teql_neigh_release(struct neighbour *n)
124 {
125 if (n)
126 neigh_release(n);
127 }
128
129 static void
130 teql_reset(struct Qdisc *sch)
131 {
132 struct teql_sched_data *dat = qdisc_priv(sch);
133
134 skb_queue_purge(&dat->q);
135 sch->q.qlen = 0;
136 }
137
138 static void
139 teql_destroy(struct Qdisc *sch)
140 {
141 struct Qdisc *q, *prev;
142 struct teql_sched_data *dat = qdisc_priv(sch);
143 struct teql_master *master = dat->m;
144
145 prev = master->slaves;
146 if (prev) {
147 do {
148 q = NEXT_SLAVE(prev);
149 if (q == sch) {
150 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
151 if (q == master->slaves) {
152 master->slaves = NEXT_SLAVE(q);
153 if (q == master->slaves) {
154 struct netdev_queue *txq;
155 spinlock_t *root_lock;
156
157 txq = netdev_get_tx_queue(master->dev, 0);
158 master->slaves = NULL;
159
160 root_lock = qdisc_root_sleeping_lock(txq->qdisc);
161 spin_lock_bh(root_lock);
162 qdisc_reset(txq->qdisc);
163 spin_unlock_bh(root_lock);
164 }
165 }
166 skb_queue_purge(&dat->q);
167 break;
168 }
169
170 } while ((prev = q) != master->slaves);
171 }
172 }
173
174 static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
175 {
176 struct net_device *dev = qdisc_dev(sch);
177 struct teql_master *m = (struct teql_master *)sch->ops;
178 struct teql_sched_data *q = qdisc_priv(sch);
179
180 if (dev->hard_header_len > m->dev->hard_header_len)
181 return -EINVAL;
182
183 if (m->dev == dev)
184 return -ELOOP;
185
186 q->m = m;
187
188 skb_queue_head_init(&q->q);
189
190 if (m->slaves) {
191 if (m->dev->flags & IFF_UP) {
192 if ((m->dev->flags & IFF_POINTOPOINT &&
193 !(dev->flags & IFF_POINTOPOINT)) ||
194 (m->dev->flags & IFF_BROADCAST &&
195 !(dev->flags & IFF_BROADCAST)) ||
196 (m->dev->flags & IFF_MULTICAST &&
197 !(dev->flags & IFF_MULTICAST)) ||
198 dev->mtu < m->dev->mtu)
199 return -EINVAL;
200 } else {
201 if (!(dev->flags&IFF_POINTOPOINT))
202 m->dev->flags &= ~IFF_POINTOPOINT;
203 if (!(dev->flags&IFF_BROADCAST))
204 m->dev->flags &= ~IFF_BROADCAST;
205 if (!(dev->flags&IFF_MULTICAST))
206 m->dev->flags &= ~IFF_MULTICAST;
207 if (dev->mtu < m->dev->mtu)
208 m->dev->mtu = dev->mtu;
209 }
210 q->next = NEXT_SLAVE(m->slaves);
211 NEXT_SLAVE(m->slaves) = sch;
212 } else {
213 q->next = sch;
214 m->slaves = sch;
215 m->dev->mtu = dev->mtu;
216 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
217 }
218 return 0;
219 }
220
221
222 static int
223 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res,
224 struct net_device *dev, struct netdev_queue *txq,
225 struct dst_entry *dst)
226 {
227 struct neighbour *n;
228 int err = 0;
229
230 n = dst_neigh_lookup_skb(dst, skb);
231 if (!n)
232 return -ENOENT;
233
234 if (dst->dev != dev) {
235 struct neighbour *mn;
236
237 mn = __neigh_lookup_errno(n->tbl, n->primary_key, dev);
238 neigh_release(n);
239 if (IS_ERR(mn))
240 return PTR_ERR(mn);
241 n = mn;
242 }
243
244 if (neigh_event_send(n, skb_res) == 0) {
245 int err;
246 char haddr[MAX_ADDR_LEN];
247
248 neigh_ha_snapshot(haddr, n, dev);
249 err = dev_hard_header(skb, dev, ntohs(skb->protocol), haddr,
250 NULL, skb->len);
251
252 if (err < 0)
253 err = -EINVAL;
254 } else {
255 err = (skb_res == NULL) ? -EAGAIN : 1;
256 }
257 neigh_release(n);
258 return err;
259 }
260
261 static inline int teql_resolve(struct sk_buff *skb,
262 struct sk_buff *skb_res,
263 struct net_device *dev,
264 struct netdev_queue *txq)
265 {
266 struct dst_entry *dst = skb_dst(skb);
267 int res;
268
269 if (txq->qdisc == &noop_qdisc)
270 return -ENODEV;
271
272 if (!dev->header_ops || !dst)
273 return 0;
274
275 rcu_read_lock();
276 res = __teql_resolve(skb, skb_res, dev, txq, dst);
277 rcu_read_unlock();
278
279 return res;
280 }
281
282 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
283 {
284 struct teql_master *master = netdev_priv(dev);
285 struct Qdisc *start, *q;
286 int busy;
287 int nores;
288 int subq = skb_get_queue_mapping(skb);
289 struct sk_buff *skb_res = NULL;
290
291 start = master->slaves;
292
293 restart:
294 nores = 0;
295 busy = 0;
296
297 q = start;
298 if (!q)
299 goto drop;
300
301 do {
302 struct net_device *slave = qdisc_dev(q);
303 struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0);
304
305 if (slave_txq->qdisc_sleeping != q)
306 continue;
307 if (netif_xmit_stopped(netdev_get_tx_queue(slave, subq)) ||
308 !netif_running(slave)) {
309 busy = 1;
310 continue;
311 }
312
313 switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
314 case 0:
315 if (__netif_tx_trylock(slave_txq)) {
316 unsigned int length = qdisc_pkt_len(skb);
317
318 if (!netif_xmit_frozen_or_stopped(slave_txq) &&
319 netdev_start_xmit(skb, slave) == NETDEV_TX_OK) {
320 txq_trans_update(slave_txq);
321 __netif_tx_unlock(slave_txq);
322 master->slaves = NEXT_SLAVE(q);
323 netif_wake_queue(dev);
324 master->tx_packets++;
325 master->tx_bytes += length;
326 return NETDEV_TX_OK;
327 }
328 __netif_tx_unlock(slave_txq);
329 }
330 if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0)))
331 busy = 1;
332 break;
333 case 1:
334 master->slaves = NEXT_SLAVE(q);
335 return NETDEV_TX_OK;
336 default:
337 nores = 1;
338 break;
339 }
340 __skb_pull(skb, skb_network_offset(skb));
341 } while ((q = NEXT_SLAVE(q)) != start);
342
343 if (nores && skb_res == NULL) {
344 skb_res = skb;
345 goto restart;
346 }
347
348 if (busy) {
349 netif_stop_queue(dev);
350 return NETDEV_TX_BUSY;
351 }
352 master->tx_errors++;
353
354 drop:
355 master->tx_dropped++;
356 dev_kfree_skb(skb);
357 return NETDEV_TX_OK;
358 }
359
360 static int teql_master_open(struct net_device *dev)
361 {
362 struct Qdisc *q;
363 struct teql_master *m = netdev_priv(dev);
364 int mtu = 0xFFFE;
365 unsigned int flags = IFF_NOARP | IFF_MULTICAST;
366
367 if (m->slaves == NULL)
368 return -EUNATCH;
369
370 flags = FMASK;
371
372 q = m->slaves;
373 do {
374 struct net_device *slave = qdisc_dev(q);
375
376 if (slave == NULL)
377 return -EUNATCH;
378
379 if (slave->mtu < mtu)
380 mtu = slave->mtu;
381 if (slave->hard_header_len > LL_MAX_HEADER)
382 return -EINVAL;
383
384 /* If all the slaves are BROADCAST, master is BROADCAST
385 If all the slaves are PtP, master is PtP
386 Otherwise, master is NBMA.
387 */
388 if (!(slave->flags&IFF_POINTOPOINT))
389 flags &= ~IFF_POINTOPOINT;
390 if (!(slave->flags&IFF_BROADCAST))
391 flags &= ~IFF_BROADCAST;
392 if (!(slave->flags&IFF_MULTICAST))
393 flags &= ~IFF_MULTICAST;
394 } while ((q = NEXT_SLAVE(q)) != m->slaves);
395
396 m->dev->mtu = mtu;
397 m->dev->flags = (m->dev->flags&~FMASK) | flags;
398 netif_start_queue(m->dev);
399 return 0;
400 }
401
402 static int teql_master_close(struct net_device *dev)
403 {
404 netif_stop_queue(dev);
405 return 0;
406 }
407
408 static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev,
409 struct rtnl_link_stats64 *stats)
410 {
411 struct teql_master *m = netdev_priv(dev);
412
413 stats->tx_packets = m->tx_packets;
414 stats->tx_bytes = m->tx_bytes;
415 stats->tx_errors = m->tx_errors;
416 stats->tx_dropped = m->tx_dropped;
417 return stats;
418 }
419
420 static int teql_master_mtu(struct net_device *dev, int new_mtu)
421 {
422 struct teql_master *m = netdev_priv(dev);
423 struct Qdisc *q;
424
425 if (new_mtu < 68)
426 return -EINVAL;
427
428 q = m->slaves;
429 if (q) {
430 do {
431 if (new_mtu > qdisc_dev(q)->mtu)
432 return -EINVAL;
433 } while ((q = NEXT_SLAVE(q)) != m->slaves);
434 }
435
436 dev->mtu = new_mtu;
437 return 0;
438 }
439
440 static const struct net_device_ops teql_netdev_ops = {
441 .ndo_open = teql_master_open,
442 .ndo_stop = teql_master_close,
443 .ndo_start_xmit = teql_master_xmit,
444 .ndo_get_stats64 = teql_master_stats64,
445 .ndo_change_mtu = teql_master_mtu,
446 };
447
448 static __init void teql_master_setup(struct net_device *dev)
449 {
450 struct teql_master *master = netdev_priv(dev);
451 struct Qdisc_ops *ops = &master->qops;
452
453 master->dev = dev;
454 ops->priv_size = sizeof(struct teql_sched_data);
455
456 ops->enqueue = teql_enqueue;
457 ops->dequeue = teql_dequeue;
458 ops->peek = teql_peek;
459 ops->init = teql_qdisc_init;
460 ops->reset = teql_reset;
461 ops->destroy = teql_destroy;
462 ops->owner = THIS_MODULE;
463
464 dev->netdev_ops = &teql_netdev_ops;
465 dev->type = ARPHRD_VOID;
466 dev->mtu = 1500;
467 dev->tx_queue_len = 100;
468 dev->flags = IFF_NOARP;
469 dev->hard_header_len = LL_MAX_HEADER;
470 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
471 }
472
473 static LIST_HEAD(master_dev_list);
474 static int max_equalizers = 1;
475 module_param(max_equalizers, int, 0);
476 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
477
478 static int __init teql_init(void)
479 {
480 int i;
481 int err = -ENODEV;
482
483 for (i = 0; i < max_equalizers; i++) {
484 struct net_device *dev;
485 struct teql_master *master;
486
487 dev = alloc_netdev(sizeof(struct teql_master), "teql%d",
488 NET_NAME_UNKNOWN, teql_master_setup);
489 if (!dev) {
490 err = -ENOMEM;
491 break;
492 }
493
494 if ((err = register_netdev(dev))) {
495 free_netdev(dev);
496 break;
497 }
498
499 master = netdev_priv(dev);
500
501 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
502 err = register_qdisc(&master->qops);
503
504 if (err) {
505 unregister_netdev(dev);
506 free_netdev(dev);
507 break;
508 }
509
510 list_add_tail(&master->master_list, &master_dev_list);
511 }
512 return i ? 0 : err;
513 }
514
515 static void __exit teql_exit(void)
516 {
517 struct teql_master *master, *nxt;
518
519 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
520
521 list_del(&master->master_list);
522
523 unregister_qdisc(&master->qops);
524 unregister_netdev(master->dev);
525 free_netdev(master->dev);
526 }
527 }
528
529 module_init(teql_init);
530 module_exit(teql_exit);
531
532 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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