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Linux 3.12.28
[linux/fpc-iii.git] / net / sched / sch_teql.c
blob474167162947acb83220c539a490c6bd62dc9e8b
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 const struct net_device_ops *slave_ops = slave->netdev_ops;
305
306 if (slave_txq->qdisc_sleeping != q)
307 continue;
308 if (netif_xmit_stopped(netdev_get_tx_queue(slave, subq)) ||
309 !netif_running(slave)) {
310 busy = 1;
311 continue;
312 }
313
314 switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
315 case 0:
316 if (__netif_tx_trylock(slave_txq)) {
317 unsigned int length = qdisc_pkt_len(skb);
318
319 if (!netif_xmit_frozen_or_stopped(slave_txq) &&
320 slave_ops->ndo_start_xmit(skb, slave) == NETDEV_TX_OK) {
321 txq_trans_update(slave_txq);
322 __netif_tx_unlock(slave_txq);
323 master->slaves = NEXT_SLAVE(q);
324 netif_wake_queue(dev);
325 master->tx_packets++;
326 master->tx_bytes += length;
327 return NETDEV_TX_OK;
328 }
329 __netif_tx_unlock(slave_txq);
330 }
331 if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0)))
332 busy = 1;
333 break;
334 case 1:
335 master->slaves = NEXT_SLAVE(q);
336 return NETDEV_TX_OK;
337 default:
338 nores = 1;
339 break;
340 }
341 __skb_pull(skb, skb_network_offset(skb));
342 } while ((q = NEXT_SLAVE(q)) != start);
343
344 if (nores && skb_res == NULL) {
345 skb_res = skb;
346 goto restart;
347 }
348
349 if (busy) {
350 netif_stop_queue(dev);
351 return NETDEV_TX_BUSY;
352 }
353 master->tx_errors++;
354
355 drop:
356 master->tx_dropped++;
357 dev_kfree_skb(skb);
358 return NETDEV_TX_OK;
359 }
360
361 static int teql_master_open(struct net_device *dev)
362 {
363 struct Qdisc *q;
364 struct teql_master *m = netdev_priv(dev);
365 int mtu = 0xFFFE;
366 unsigned int flags = IFF_NOARP | IFF_MULTICAST;
367
368 if (m->slaves == NULL)
369 return -EUNATCH;
370
371 flags = FMASK;
372
373 q = m->slaves;
374 do {
375 struct net_device *slave = qdisc_dev(q);
376
377 if (slave == NULL)
378 return -EUNATCH;
379
380 if (slave->mtu < mtu)
381 mtu = slave->mtu;
382 if (slave->hard_header_len > LL_MAX_HEADER)
383 return -EINVAL;
384
385 /* If all the slaves are BROADCAST, master is BROADCAST
386 If all the slaves are PtP, master is PtP
387 Otherwise, master is NBMA.
388 */
389 if (!(slave->flags&IFF_POINTOPOINT))
390 flags &= ~IFF_POINTOPOINT;
391 if (!(slave->flags&IFF_BROADCAST))
392 flags &= ~IFF_BROADCAST;
393 if (!(slave->flags&IFF_MULTICAST))
394 flags &= ~IFF_MULTICAST;
395 } while ((q = NEXT_SLAVE(q)) != m->slaves);
396
397 m->dev->mtu = mtu;
398 m->dev->flags = (m->dev->flags&~FMASK) | flags;
399 netif_start_queue(m->dev);
400 return 0;
401 }
402
403 static int teql_master_close(struct net_device *dev)
404 {
405 netif_stop_queue(dev);
406 return 0;
407 }
408
409 static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev,
410 struct rtnl_link_stats64 *stats)
411 {
412 struct teql_master *m = netdev_priv(dev);
413
414 stats->tx_packets = m->tx_packets;
415 stats->tx_bytes = m->tx_bytes;
416 stats->tx_errors = m->tx_errors;
417 stats->tx_dropped = m->tx_dropped;
418 return stats;
419 }
420
421 static int teql_master_mtu(struct net_device *dev, int new_mtu)
422 {
423 struct teql_master *m = netdev_priv(dev);
424 struct Qdisc *q;
425
426 if (new_mtu < 68)
427 return -EINVAL;
428
429 q = m->slaves;
430 if (q) {
431 do {
432 if (new_mtu > qdisc_dev(q)->mtu)
433 return -EINVAL;
434 } while ((q = NEXT_SLAVE(q)) != m->slaves);
435 }
436
437 dev->mtu = new_mtu;
438 return 0;
439 }
440
441 static const struct net_device_ops teql_netdev_ops = {
442 .ndo_open = teql_master_open,
443 .ndo_stop = teql_master_close,
444 .ndo_start_xmit = teql_master_xmit,
445 .ndo_get_stats64 = teql_master_stats64,
446 .ndo_change_mtu = teql_master_mtu,
447 };
448
449 static __init void teql_master_setup(struct net_device *dev)
450 {
451 struct teql_master *master = netdev_priv(dev);
452 struct Qdisc_ops *ops = &master->qops;
453
454 master->dev = dev;
455 ops->priv_size = sizeof(struct teql_sched_data);
456
457 ops->enqueue = teql_enqueue;
458 ops->dequeue = teql_dequeue;
459 ops->peek = teql_peek;
460 ops->init = teql_qdisc_init;
461 ops->reset = teql_reset;
462 ops->destroy = teql_destroy;
463 ops->owner = THIS_MODULE;
464
465 dev->netdev_ops = &teql_netdev_ops;
466 dev->type = ARPHRD_VOID;
467 dev->mtu = 1500;
468 dev->tx_queue_len = 100;
469 dev->flags = IFF_NOARP;
470 dev->hard_header_len = LL_MAX_HEADER;
471 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
472 }
473
474 static LIST_HEAD(master_dev_list);
475 static int max_equalizers = 1;
476 module_param(max_equalizers, int, 0);
477 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
478
479 static int __init teql_init(void)
480 {
481 int i;
482 int err = -ENODEV;
483
484 for (i = 0; i < max_equalizers; i++) {
485 struct net_device *dev;
486 struct teql_master *master;
487
488 dev = alloc_netdev(sizeof(struct teql_master),
489 "teql%d", teql_master_setup);
490 if (!dev) {
491 err = -ENOMEM;
492 break;
493 }
494
495 if ((err = register_netdev(dev))) {
496 free_netdev(dev);
497 break;
498 }
499
500 master = netdev_priv(dev);
501
502 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
503 err = register_qdisc(&master->qops);
504
505 if (err) {
506 unregister_netdev(dev);
507 free_netdev(dev);
508 break;
509 }
510
511 list_add_tail(&master->master_list, &master_dev_list);
512 }
513 return i ? 0 : err;
514 }
515
516 static void __exit teql_exit(void)
517 {
518 struct teql_master *master, *nxt;
519
520 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
521
522 list_del(&master->master_list);
523
524 unregister_qdisc(&master->qops);
525 unregister_netdev(master->dev);
526 free_netdev(master->dev);
527 }
528 }
529
530 module_init(teql_init);
531 module_exit(teql_exit);
532
533 MODULE_LICENSE("GPL");
Linux with added FPC-III support