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s390/mm: fix page table upgrade vs 2ndary address mode accesses
[linux/fpc-iii.git] / net / sched / sch_teql.c
blob93f04cf5cac12f4f76f7d5e9fb0b286d0632948e
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, struct sk_buff **to_free)
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, to_free);
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 struct Qdisc *q;
100
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);
104
105 if (skb == NULL) {
106 struct net_device *m = qdisc_dev(q);
107 if (m) {
108 dat->m->slaves = sch;
109 netif_wake_queue(m);
110 }
111 } else {
112 qdisc_bstats_update(sch, skb);
113 }
114 sch->q.qlen = dat->q.qlen + q->q.qlen;
115 return skb;
116 }
117
118 static struct sk_buff *
119 teql_peek(struct Qdisc *sch)
120 {
121 /* teql is meant to be used as root qdisc */
122 return NULL;
123 }
124
125 static void
126 teql_reset(struct Qdisc *sch)
127 {
128 struct teql_sched_data *dat = qdisc_priv(sch);
129
130 skb_queue_purge(&dat->q);
131 sch->q.qlen = 0;
132 }
133
134 static void
135 teql_destroy(struct Qdisc *sch)
136 {
137 struct Qdisc *q, *prev;
138 struct teql_sched_data *dat = qdisc_priv(sch);
139 struct teql_master *master = dat->m;
140
141 prev = master->slaves;
142 if (prev) {
143 do {
144 q = NEXT_SLAVE(prev);
145 if (q == sch) {
146 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
147 if (q == master->slaves) {
148 master->slaves = NEXT_SLAVE(q);
149 if (q == master->slaves) {
150 struct netdev_queue *txq;
151 spinlock_t *root_lock;
152
153 txq = netdev_get_tx_queue(master->dev, 0);
154 master->slaves = NULL;
155
156 root_lock = qdisc_root_sleeping_lock(rtnl_dereference(txq->qdisc));
157 spin_lock_bh(root_lock);
158 qdisc_reset(rtnl_dereference(txq->qdisc));
159 spin_unlock_bh(root_lock);
160 }
161 }
162 skb_queue_purge(&dat->q);
163 break;
164 }
165
166 } while ((prev = q) != master->slaves);
167 }
168 }
169
170 static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt,
171 struct netlink_ext_ack *extack)
172 {
173 struct net_device *dev = qdisc_dev(sch);
174 struct teql_master *m = (struct teql_master *)sch->ops;
175 struct teql_sched_data *q = qdisc_priv(sch);
176
177 if (dev->hard_header_len > m->dev->hard_header_len)
178 return -EINVAL;
179
180 if (m->dev == dev)
181 return -ELOOP;
182
183 q->m = m;
184
185 skb_queue_head_init(&q->q);
186
187 if (m->slaves) {
188 if (m->dev->flags & IFF_UP) {
189 if ((m->dev->flags & IFF_POINTOPOINT &&
190 !(dev->flags & IFF_POINTOPOINT)) ||
191 (m->dev->flags & IFF_BROADCAST &&
192 !(dev->flags & IFF_BROADCAST)) ||
193 (m->dev->flags & IFF_MULTICAST &&
194 !(dev->flags & IFF_MULTICAST)) ||
195 dev->mtu < m->dev->mtu)
196 return -EINVAL;
197 } else {
198 if (!(dev->flags&IFF_POINTOPOINT))
199 m->dev->flags &= ~IFF_POINTOPOINT;
200 if (!(dev->flags&IFF_BROADCAST))
201 m->dev->flags &= ~IFF_BROADCAST;
202 if (!(dev->flags&IFF_MULTICAST))
203 m->dev->flags &= ~IFF_MULTICAST;
204 if (dev->mtu < m->dev->mtu)
205 m->dev->mtu = dev->mtu;
206 }
207 q->next = NEXT_SLAVE(m->slaves);
208 NEXT_SLAVE(m->slaves) = sch;
209 } else {
210 q->next = sch;
211 m->slaves = sch;
212 m->dev->mtu = dev->mtu;
213 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
214 }
215 return 0;
216 }
217
218
219 static int
220 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res,
221 struct net_device *dev, struct netdev_queue *txq,
222 struct dst_entry *dst)
223 {
224 struct neighbour *n;
225 int err = 0;
226
227 n = dst_neigh_lookup_skb(dst, skb);
228 if (!n)
229 return -ENOENT;
230
231 if (dst->dev != dev) {
232 struct neighbour *mn;
233
234 mn = __neigh_lookup_errno(n->tbl, n->primary_key, dev);
235 neigh_release(n);
236 if (IS_ERR(mn))
237 return PTR_ERR(mn);
238 n = mn;
239 }
240
241 if (neigh_event_send(n, skb_res) == 0) {
242 int err;
243 char haddr[MAX_ADDR_LEN];
244
245 neigh_ha_snapshot(haddr, n, dev);
246 err = dev_hard_header(skb, dev, ntohs(tc_skb_protocol(skb)),
247 haddr, NULL, skb->len);
248
249 if (err < 0)
250 err = -EINVAL;
251 } else {
252 err = (skb_res == NULL) ? -EAGAIN : 1;
253 }
254 neigh_release(n);
255 return err;
256 }
257
258 static inline int teql_resolve(struct sk_buff *skb,
259 struct sk_buff *skb_res,
260 struct net_device *dev,
261 struct netdev_queue *txq)
262 {
263 struct dst_entry *dst = skb_dst(skb);
264 int res;
265
266 if (rcu_access_pointer(txq->qdisc) == &noop_qdisc)
267 return -ENODEV;
268
269 if (!dev->header_ops || !dst)
270 return 0;
271
272 rcu_read_lock();
273 res = __teql_resolve(skb, skb_res, dev, txq, dst);
274 rcu_read_unlock();
275
276 return res;
277 }
278
279 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
280 {
281 struct teql_master *master = netdev_priv(dev);
282 struct Qdisc *start, *q;
283 int busy;
284 int nores;
285 int subq = skb_get_queue_mapping(skb);
286 struct sk_buff *skb_res = NULL;
287
288 start = master->slaves;
289
290 restart:
291 nores = 0;
292 busy = 0;
293
294 q = start;
295 if (!q)
296 goto drop;
297
298 do {
299 struct net_device *slave = qdisc_dev(q);
300 struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0);
301
302 if (slave_txq->qdisc_sleeping != q)
303 continue;
304 if (netif_xmit_stopped(netdev_get_tx_queue(slave, subq)) ||
305 !netif_running(slave)) {
306 busy = 1;
307 continue;
308 }
309
310 switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
311 case 0:
312 if (__netif_tx_trylock(slave_txq)) {
313 unsigned int length = qdisc_pkt_len(skb);
314
315 if (!netif_xmit_frozen_or_stopped(slave_txq) &&
316 netdev_start_xmit(skb, slave, slave_txq, false) ==
317 NETDEV_TX_OK) {
318 __netif_tx_unlock(slave_txq);
319 master->slaves = NEXT_SLAVE(q);
320 netif_wake_queue(dev);
321 master->tx_packets++;
322 master->tx_bytes += length;
323 return NETDEV_TX_OK;
324 }
325 __netif_tx_unlock(slave_txq);
326 }
327 if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0)))
328 busy = 1;
329 break;
330 case 1:
331 master->slaves = NEXT_SLAVE(q);
332 return NETDEV_TX_OK;
333 default:
334 nores = 1;
335 break;
336 }
337 __skb_pull(skb, skb_network_offset(skb));
338 } while ((q = NEXT_SLAVE(q)) != start);
339
340 if (nores && skb_res == NULL) {
341 skb_res = skb;
342 goto restart;
343 }
344
345 if (busy) {
346 netif_stop_queue(dev);
347 return NETDEV_TX_BUSY;
348 }
349 master->tx_errors++;
350
351 drop:
352 master->tx_dropped++;
353 dev_kfree_skb(skb);
354 return NETDEV_TX_OK;
355 }
356
357 static int teql_master_open(struct net_device *dev)
358 {
359 struct Qdisc *q;
360 struct teql_master *m = netdev_priv(dev);
361 int mtu = 0xFFFE;
362 unsigned int flags = IFF_NOARP | IFF_MULTICAST;
363
364 if (m->slaves == NULL)
365 return -EUNATCH;
366
367 flags = FMASK;
368
369 q = m->slaves;
370 do {
371 struct net_device *slave = qdisc_dev(q);
372
373 if (slave == NULL)
374 return -EUNATCH;
375
376 if (slave->mtu < mtu)
377 mtu = slave->mtu;
378 if (slave->hard_header_len > LL_MAX_HEADER)
379 return -EINVAL;
380
381 /* If all the slaves are BROADCAST, master is BROADCAST
382 If all the slaves are PtP, master is PtP
383 Otherwise, master is NBMA.
384 */
385 if (!(slave->flags&IFF_POINTOPOINT))
386 flags &= ~IFF_POINTOPOINT;
387 if (!(slave->flags&IFF_BROADCAST))
388 flags &= ~IFF_BROADCAST;
389 if (!(slave->flags&IFF_MULTICAST))
390 flags &= ~IFF_MULTICAST;
391 } while ((q = NEXT_SLAVE(q)) != m->slaves);
392
393 m->dev->mtu = mtu;
394 m->dev->flags = (m->dev->flags&~FMASK) | flags;
395 netif_start_queue(m->dev);
396 return 0;
397 }
398
399 static int teql_master_close(struct net_device *dev)
400 {
401 netif_stop_queue(dev);
402 return 0;
403 }
404
405 static void teql_master_stats64(struct net_device *dev,
406 struct rtnl_link_stats64 *stats)
407 {
408 struct teql_master *m = netdev_priv(dev);
409
410 stats->tx_packets = m->tx_packets;
411 stats->tx_bytes = m->tx_bytes;
412 stats->tx_errors = m->tx_errors;
413 stats->tx_dropped = m->tx_dropped;
414 }
415
416 static int teql_master_mtu(struct net_device *dev, int new_mtu)
417 {
418 struct teql_master *m = netdev_priv(dev);
419 struct Qdisc *q;
420
421 q = m->slaves;
422 if (q) {
423 do {
424 if (new_mtu > qdisc_dev(q)->mtu)
425 return -EINVAL;
426 } while ((q = NEXT_SLAVE(q)) != m->slaves);
427 }
428
429 dev->mtu = new_mtu;
430 return 0;
431 }
432
433 static const struct net_device_ops teql_netdev_ops = {
434 .ndo_open = teql_master_open,
435 .ndo_stop = teql_master_close,
436 .ndo_start_xmit = teql_master_xmit,
437 .ndo_get_stats64 = teql_master_stats64,
438 .ndo_change_mtu = teql_master_mtu,
439 };
440
441 static __init void teql_master_setup(struct net_device *dev)
442 {
443 struct teql_master *master = netdev_priv(dev);
444 struct Qdisc_ops *ops = &master->qops;
445
446 master->dev = dev;
447 ops->priv_size = sizeof(struct teql_sched_data);
448
449 ops->enqueue = teql_enqueue;
450 ops->dequeue = teql_dequeue;
451 ops->peek = teql_peek;
452 ops->init = teql_qdisc_init;
453 ops->reset = teql_reset;
454 ops->destroy = teql_destroy;
455 ops->owner = THIS_MODULE;
456
457 dev->netdev_ops = &teql_netdev_ops;
458 dev->type = ARPHRD_VOID;
459 dev->mtu = 1500;
460 dev->min_mtu = 68;
461 dev->max_mtu = 65535;
462 dev->tx_queue_len = 100;
463 dev->flags = IFF_NOARP;
464 dev->hard_header_len = LL_MAX_HEADER;
465 netif_keep_dst(dev);
466 }
467
468 static LIST_HEAD(master_dev_list);
469 static int max_equalizers = 1;
470 module_param(max_equalizers, int, 0);
471 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
472
473 static int __init teql_init(void)
474 {
475 int i;
476 int err = -ENODEV;
477
478 for (i = 0; i < max_equalizers; i++) {
479 struct net_device *dev;
480 struct teql_master *master;
481
482 dev = alloc_netdev(sizeof(struct teql_master), "teql%d",
483 NET_NAME_UNKNOWN, teql_master_setup);
484 if (!dev) {
485 err = -ENOMEM;
486 break;
487 }
488
489 if ((err = register_netdev(dev))) {
490 free_netdev(dev);
491 break;
492 }
493
494 master = netdev_priv(dev);
495
496 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
497 err = register_qdisc(&master->qops);
498
499 if (err) {
500 unregister_netdev(dev);
501 free_netdev(dev);
502 break;
503 }
504
505 list_add_tail(&master->master_list, &master_dev_list);
506 }
507 return i ? 0 : err;
508 }
509
510 static void __exit teql_exit(void)
511 {
512 struct teql_master *master, *nxt;
513
514 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
515
516 list_del(&master->master_list);
517
518 unregister_qdisc(&master->qops);
519 unregister_netdev(master->dev);
520 free_netdev(master->dev);
521 }
522 }
523
524 module_init(teql_init);
525 module_exit(teql_exit);
526
527 MODULE_LICENSE("GPL");
Linux with added FPC-III support