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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
56struct 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
67struct teql_sched_data {
68 struct Qdisc *next;
69 struct teql_master *m;
70 struct neighbour *ncache;
71 struct sk_buff_head q;
72};
73
74#define NEXT_SLAVE(q) (((struct teql_sched_data *)qdisc_priv(q))->next)
75
76#define FMASK (IFF_BROADCAST | IFF_POINTOPOINT)
77
78/* "teql*" qdisc routines */
79
80static int
81teql_enqueue(struct sk_buff *skb, struct Qdisc *sch)
82{
83 struct net_device *dev = qdisc_dev(sch);
84 struct teql_sched_data *q = qdisc_priv(sch);
85
86 if (q->q.qlen < dev->tx_queue_len) {
87 __skb_queue_tail(&q->q, skb);
88 return NET_XMIT_SUCCESS;
89 }
90
91 return qdisc_drop(skb, sch);
92}
93
94static struct sk_buff *
95teql_dequeue(struct Qdisc *sch)
96{
97 struct teql_sched_data *dat = qdisc_priv(sch);
98 struct netdev_queue *dat_queue;
99 struct sk_buff *skb;
100
101 skb = __skb_dequeue(&dat->q);
102 dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
103 if (skb == NULL) {
104 struct net_device *m = qdisc_dev(dat_queue->qdisc);
105 if (m) {
106 dat->m->slaves = sch;
107 netif_wake_queue(m);
108 }
109 } else {
110 qdisc_bstats_update(sch, skb);
111 }
112 sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen;
113 return skb;
114}
115
116static struct sk_buff *
117teql_peek(struct Qdisc *sch)
118{
119 /* teql is meant to be used as root qdisc */
120 return NULL;
121}
122
123static inline void
124teql_neigh_release(struct neighbour *n)
125{
126 if (n)
127 neigh_release(n);
128}
129
130static void
131teql_reset(struct Qdisc *sch)
132{
133 struct teql_sched_data *dat = qdisc_priv(sch);
134
135 skb_queue_purge(&dat->q);
136 sch->q.qlen = 0;
137 teql_neigh_release(xchg(&dat->ncache, NULL));
138}
139
140static void
141teql_destroy(struct Qdisc *sch)
142{
143 struct Qdisc *q, *prev;
144 struct teql_sched_data *dat = qdisc_priv(sch);
145 struct teql_master *master = dat->m;
146
147 prev = master->slaves;
148 if (prev) {
149 do {
150 q = NEXT_SLAVE(prev);
151 if (q == sch) {
152 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
153 if (q == master->slaves) {
154 master->slaves = NEXT_SLAVE(q);
155 if (q == master->slaves) {
156 struct netdev_queue *txq;
157 spinlock_t *root_lock;
158
159 txq = netdev_get_tx_queue(master->dev, 0);
160 master->slaves = NULL;
161
162 root_lock = qdisc_root_sleeping_lock(txq->qdisc);
163 spin_lock_bh(root_lock);
164 qdisc_reset(txq->qdisc);
165 spin_unlock_bh(root_lock);
166 }
167 }
168 skb_queue_purge(&dat->q);
169 teql_neigh_release(xchg(&dat->ncache, NULL));
170 break;
171 }
172
173 } while ((prev = q) != master->slaves);
174 }
175}
176
177static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt)
178{
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);
182
183 if (dev->hard_header_len > m->dev->hard_header_len)
184 return -EINVAL;
185
186 if (m->dev == dev)
187 return -ELOOP;
188
189 q->m = m;
190
191 skb_queue_head_init(&q->q);
192
193 if (m->slaves) {
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)
202 return -EINVAL;
203 } else {
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;
212 }
213 q->next = NEXT_SLAVE(m->slaves);
214 NEXT_SLAVE(m->slaves) = sch;
215 } else {
216 q->next = sch;
217 m->slaves = sch;
218 m->dev->mtu = dev->mtu;
219 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
220 }
221 return 0;
222}
223
224
225static int
226__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res,
227 struct net_device *dev, struct netdev_queue *txq,
228 struct neighbour *mn)
229{
230 struct teql_sched_data *q = qdisc_priv(txq->qdisc);
231 struct neighbour *n = q->ncache;
232
233 if (mn->tbl == NULL)
234 return -EINVAL;
235 if (n && n->tbl == mn->tbl &&
236 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) {
237 atomic_inc(&n->refcnt);
238 } else {
239 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev);
240 if (IS_ERR(n))
241 return PTR_ERR(n);
242 }
243 if (neigh_event_send(n, skb_res) == 0) {
244 int err;
245 char haddr[MAX_ADDR_LEN];
246
247 neigh_ha_snapshot(haddr, n, dev);
248 err = dev_hard_header(skb, dev, ntohs(skb->protocol), haddr,
249 NULL, skb->len);
250
251 if (err < 0) {
252 neigh_release(n);
253 return -EINVAL;
254 }
255 teql_neigh_release(xchg(&q->ncache, n));
256 return 0;
257 }
258 neigh_release(n);
259 return (skb_res == NULL) ? -EAGAIN : 1;
260}
261
262static inline int teql_resolve(struct sk_buff *skb,
263 struct sk_buff *skb_res,
264 struct net_device *dev,
265 struct netdev_queue *txq)
266{
267 struct dst_entry *dst = skb_dst(skb);
268 struct neighbour *mn;
269 int res;
270
271 if (txq->qdisc == &noop_qdisc)
272 return -ENODEV;
273
274 if (!dev->header_ops || !dst)
275 return 0;
276
277 rcu_read_lock();
278 mn = dst_get_neighbour_noref(dst);
279 res = mn ? __teql_resolve(skb, skb_res, dev, txq, mn) : 0;
280 rcu_read_unlock();
281
282 return res;
283}
284
285static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
286{
287 struct teql_master *master = netdev_priv(dev);
288 struct Qdisc *start, *q;
289 int busy;
290 int nores;
291 int subq = skb_get_queue_mapping(skb);
292 struct sk_buff *skb_res = NULL;
293
294 start = master->slaves;
295
296restart:
297 nores = 0;
298 busy = 0;
299
300 q = start;
301 if (!q)
302 goto drop;
303
304 do {
305 struct net_device *slave = qdisc_dev(q);
306 struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0);
307 const struct net_device_ops *slave_ops = slave->netdev_ops;
308
309 if (slave_txq->qdisc_sleeping != q)
310 continue;
311 if (netif_xmit_stopped(netdev_get_tx_queue(slave, subq)) ||
312 !netif_running(slave)) {
313 busy = 1;
314 continue;
315 }
316
317 switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
318 case 0:
319 if (__netif_tx_trylock(slave_txq)) {
320 unsigned int length = qdisc_pkt_len(skb);
321
322 if (!netif_xmit_frozen_or_stopped(slave_txq) &&
323 slave_ops->ndo_start_xmit(skb, slave) == NETDEV_TX_OK) {
324 txq_trans_update(slave_txq);
325 __netif_tx_unlock(slave_txq);
326 master->slaves = NEXT_SLAVE(q);
327 netif_wake_queue(dev);
328 master->tx_packets++;
329 master->tx_bytes += length;
330 return NETDEV_TX_OK;
331 }
332 __netif_tx_unlock(slave_txq);
333 }
334 if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0)))
335 busy = 1;
336 break;
337 case 1:
338 master->slaves = NEXT_SLAVE(q);
339 return NETDEV_TX_OK;
340 default:
341 nores = 1;
342 break;
343 }
344 __skb_pull(skb, skb_network_offset(skb));
345 } while ((q = NEXT_SLAVE(q)) != start);
346
347 if (nores && skb_res == NULL) {
348 skb_res = skb;
349 goto restart;
350 }
351
352 if (busy) {
353 netif_stop_queue(dev);
354 return NETDEV_TX_BUSY;
355 }
356 master->tx_errors++;
357
358drop:
359 master->tx_dropped++;
360 dev_kfree_skb(skb);
361 return NETDEV_TX_OK;
362}
363
364static int teql_master_open(struct net_device *dev)
365{
366 struct Qdisc *q;
367 struct teql_master *m = netdev_priv(dev);
368 int mtu = 0xFFFE;
369 unsigned int flags = IFF_NOARP | IFF_MULTICAST;
370
371 if (m->slaves == NULL)
372 return -EUNATCH;
373
374 flags = FMASK;
375
376 q = m->slaves;
377 do {
378 struct net_device *slave = qdisc_dev(q);
379
380 if (slave == NULL)
381 return -EUNATCH;
382
383 if (slave->mtu < mtu)
384 mtu = slave->mtu;
385 if (slave->hard_header_len > LL_MAX_HEADER)
386 return -EINVAL;
387
388 /* If all the slaves are BROADCAST, master is BROADCAST
389 If all the slaves are PtP, master is PtP
390 Otherwise, master is NBMA.
391 */
392 if (!(slave->flags&IFF_POINTOPOINT))
393 flags &= ~IFF_POINTOPOINT;
394 if (!(slave->flags&IFF_BROADCAST))
395 flags &= ~IFF_BROADCAST;
396 if (!(slave->flags&IFF_MULTICAST))
397 flags &= ~IFF_MULTICAST;
398 } while ((q = NEXT_SLAVE(q)) != m->slaves);
399
400 m->dev->mtu = mtu;
401 m->dev->flags = (m->dev->flags&~FMASK) | flags;
402 netif_start_queue(m->dev);
403 return 0;
404}
405
406static int teql_master_close(struct net_device *dev)
407{
408 netif_stop_queue(dev);
409 return 0;
410}
411
412static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev,
413 struct rtnl_link_stats64 *stats)
414{
415 struct teql_master *m = netdev_priv(dev);
416
417 stats->tx_packets = m->tx_packets;
418 stats->tx_bytes = m->tx_bytes;
419 stats->tx_errors = m->tx_errors;
420 stats->tx_dropped = m->tx_dropped;
421 return stats;
422}
423
424static int teql_master_mtu(struct net_device *dev, int new_mtu)
425{
426 struct teql_master *m = netdev_priv(dev);
427 struct Qdisc *q;
428
429 if (new_mtu < 68)
430 return -EINVAL;
431
432 q = m->slaves;
433 if (q) {
434 do {
435 if (new_mtu > qdisc_dev(q)->mtu)
436 return -EINVAL;
437 } while ((q = NEXT_SLAVE(q)) != m->slaves);
438 }
439
440 dev->mtu = new_mtu;
441 return 0;
442}
443
444static const struct net_device_ops teql_netdev_ops = {
445 .ndo_open = teql_master_open,
446 .ndo_stop = teql_master_close,
447 .ndo_start_xmit = teql_master_xmit,
448 .ndo_get_stats64 = teql_master_stats64,
449 .ndo_change_mtu = teql_master_mtu,
450};
451
452static __init void teql_master_setup(struct net_device *dev)
453{
454 struct teql_master *master = netdev_priv(dev);
455 struct Qdisc_ops *ops = &master->qops;
456
457 master->dev = dev;
458 ops->priv_size = sizeof(struct teql_sched_data);
459
460 ops->enqueue = teql_enqueue;
461 ops->dequeue = teql_dequeue;
462 ops->peek = teql_peek;
463 ops->init = teql_qdisc_init;
464 ops->reset = teql_reset;
465 ops->destroy = teql_destroy;
466 ops->owner = THIS_MODULE;
467
468 dev->netdev_ops = &teql_netdev_ops;
469 dev->type = ARPHRD_VOID;
470 dev->mtu = 1500;
471 dev->tx_queue_len = 100;
472 dev->flags = IFF_NOARP;
473 dev->hard_header_len = LL_MAX_HEADER;
474 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
475}
476
477static LIST_HEAD(master_dev_list);
478static int max_equalizers = 1;
479module_param(max_equalizers, int, 0);
480MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
481
482static int __init teql_init(void)
483{
484 int i;
485 int err = -ENODEV;
486
487 for (i = 0; i < max_equalizers; i++) {
488 struct net_device *dev;
489 struct teql_master *master;
490
491 dev = alloc_netdev(sizeof(struct teql_master),
492 "teql%d", teql_master_setup);
493 if (!dev) {
494 err = -ENOMEM;
495 break;
496 }
497
498 if ((err = register_netdev(dev))) {
499 free_netdev(dev);
500 break;
501 }
502
503 master = netdev_priv(dev);
504
505 strlcpy(master->qops.id, dev->name, IFNAMSIZ);
506 err = register_qdisc(&master->qops);
507
508 if (err) {
509 unregister_netdev(dev);
510 free_netdev(dev);
511 break;
512 }
513
514 list_add_tail(&master->master_list, &master_dev_list);
515 }
516 return i ? 0 : err;
517}
518
519static void __exit teql_exit(void)
520{
521 struct teql_master *master, *nxt;
522
523 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
524
525 list_del(&master->master_list);
526
527 unregister_qdisc(&master->qops);
528 unregister_netdev(master->dev);
529 free_netdev(master->dev);
530 }
531}
532
533module_init(teql_init);
534module_exit(teql_exit);
535
536MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* net/sched/sch_teql.c "True" (or "trivial") link equalizer.
3 *
4 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
5 */
6
7#include <linux/module.h>
8#include <linux/types.h>
9#include <linux/kernel.h>
10#include <linux/slab.h>
11#include <linux/string.h>
12#include <linux/errno.h>
13#include <linux/if_arp.h>
14#include <linux/netdevice.h>
15#include <linux/init.h>
16#include <linux/skbuff.h>
17#include <linux/moduleparam.h>
18#include <net/dst.h>
19#include <net/neighbour.h>
20#include <net/pkt_sched.h>
21
22/*
23 How to setup it.
24 ----------------
25
26 After loading this module you will find a new device teqlN
27 and new qdisc with the same name. To join a slave to the equalizer
28 you should just set this qdisc on a device f.e.
29
30 # tc qdisc add dev eth0 root teql0
31 # tc qdisc add dev eth1 root teql0
32
33 That's all. Full PnP 8)
34
35 Applicability.
36 --------------
37
38 1. Slave devices MUST be active devices, i.e., they must raise the tbusy
39 signal and generate EOI events. If you want to equalize virtual devices
40 like tunnels, use a normal eql device.
41 2. This device puts no limitations on physical slave characteristics
42 f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-)
43 Certainly, large difference in link speeds will make the resulting
44 eqalized link unusable, because of huge packet reordering.
45 I estimate an upper useful difference as ~10 times.
46 3. If the slave requires address resolution, only protocols using
47 neighbour cache (IPv4/IPv6) will work over the equalized link.
48 Other protocols are still allowed to use the slave device directly,
49 which will not break load balancing, though native slave
50 traffic will have the highest priority. */
51
52struct teql_master {
53 struct Qdisc_ops qops;
54 struct net_device *dev;
55 struct Qdisc *slaves;
56 struct list_head master_list;
57 unsigned long tx_bytes;
58 unsigned long tx_packets;
59 unsigned long tx_errors;
60 unsigned long tx_dropped;
61};
62
63struct teql_sched_data {
64 struct Qdisc *next;
65 struct teql_master *m;
66 struct sk_buff_head q;
67};
68
69#define NEXT_SLAVE(q) (((struct teql_sched_data *)qdisc_priv(q))->next)
70
71#define FMASK (IFF_BROADCAST | IFF_POINTOPOINT)
72
73/* "teql*" qdisc routines */
74
75static int
76teql_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
77{
78 struct net_device *dev = qdisc_dev(sch);
79 struct teql_sched_data *q = qdisc_priv(sch);
80
81 if (q->q.qlen < READ_ONCE(dev->tx_queue_len)) {
82 __skb_queue_tail(&q->q, skb);
83 return NET_XMIT_SUCCESS;
84 }
85
86 return qdisc_drop(skb, sch, to_free);
87}
88
89static struct sk_buff *
90teql_dequeue(struct Qdisc *sch)
91{
92 struct teql_sched_data *dat = qdisc_priv(sch);
93 struct netdev_queue *dat_queue;
94 struct sk_buff *skb;
95 struct Qdisc *q;
96
97 skb = __skb_dequeue(&dat->q);
98 dat_queue = netdev_get_tx_queue(dat->m->dev, 0);
99 q = rcu_dereference_bh(dat_queue->qdisc);
100
101 if (skb == NULL) {
102 struct net_device *m = qdisc_dev(q);
103 if (m) {
104 dat->m->slaves = sch;
105 netif_wake_queue(m);
106 }
107 } else {
108 qdisc_bstats_update(sch, skb);
109 }
110 sch->q.qlen = dat->q.qlen + q->q.qlen;
111 return skb;
112}
113
114static struct sk_buff *
115teql_peek(struct Qdisc *sch)
116{
117 /* teql is meant to be used as root qdisc */
118 return NULL;
119}
120
121static void
122teql_reset(struct Qdisc *sch)
123{
124 struct teql_sched_data *dat = qdisc_priv(sch);
125
126 skb_queue_purge(&dat->q);
127}
128
129static void
130teql_destroy(struct Qdisc *sch)
131{
132 struct Qdisc *q, *prev;
133 struct teql_sched_data *dat = qdisc_priv(sch);
134 struct teql_master *master = dat->m;
135
136 if (!master)
137 return;
138
139 prev = master->slaves;
140 if (prev) {
141 do {
142 q = NEXT_SLAVE(prev);
143 if (q == sch) {
144 NEXT_SLAVE(prev) = NEXT_SLAVE(q);
145 if (q == master->slaves) {
146 master->slaves = NEXT_SLAVE(q);
147 if (q == master->slaves) {
148 struct netdev_queue *txq;
149 spinlock_t *root_lock;
150
151 txq = netdev_get_tx_queue(master->dev, 0);
152 master->slaves = NULL;
153
154 root_lock = qdisc_root_sleeping_lock(rtnl_dereference(txq->qdisc));
155 spin_lock_bh(root_lock);
156 qdisc_reset(rtnl_dereference(txq->qdisc));
157 spin_unlock_bh(root_lock);
158 }
159 }
160 skb_queue_purge(&dat->q);
161 break;
162 }
163
164 } while ((prev = q) != master->slaves);
165 }
166}
167
168static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt,
169 struct netlink_ext_ack *extack)
170{
171 struct net_device *dev = qdisc_dev(sch);
172 struct teql_master *m = (struct teql_master *)sch->ops;
173 struct teql_sched_data *q = qdisc_priv(sch);
174
175 if (dev->hard_header_len > m->dev->hard_header_len)
176 return -EINVAL;
177
178 if (m->dev == dev)
179 return -ELOOP;
180
181 q->m = m;
182
183 skb_queue_head_init(&q->q);
184
185 if (m->slaves) {
186 if (m->dev->flags & IFF_UP) {
187 if ((m->dev->flags & IFF_POINTOPOINT &&
188 !(dev->flags & IFF_POINTOPOINT)) ||
189 (m->dev->flags & IFF_BROADCAST &&
190 !(dev->flags & IFF_BROADCAST)) ||
191 (m->dev->flags & IFF_MULTICAST &&
192 !(dev->flags & IFF_MULTICAST)) ||
193 dev->mtu < m->dev->mtu)
194 return -EINVAL;
195 } else {
196 if (!(dev->flags&IFF_POINTOPOINT))
197 m->dev->flags &= ~IFF_POINTOPOINT;
198 if (!(dev->flags&IFF_BROADCAST))
199 m->dev->flags &= ~IFF_BROADCAST;
200 if (!(dev->flags&IFF_MULTICAST))
201 m->dev->flags &= ~IFF_MULTICAST;
202 if (dev->mtu < m->dev->mtu)
203 m->dev->mtu = dev->mtu;
204 }
205 q->next = NEXT_SLAVE(m->slaves);
206 NEXT_SLAVE(m->slaves) = sch;
207 } else {
208 q->next = sch;
209 m->slaves = sch;
210 m->dev->mtu = dev->mtu;
211 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK);
212 }
213 return 0;
214}
215
216
217static int
218__teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res,
219 struct net_device *dev, struct netdev_queue *txq,
220 struct dst_entry *dst)
221{
222 struct neighbour *n;
223 int err = 0;
224
225 n = dst_neigh_lookup_skb(dst, skb);
226 if (!n)
227 return -ENOENT;
228
229 if (dst->dev != dev) {
230 struct neighbour *mn;
231
232 mn = __neigh_lookup_errno(n->tbl, n->primary_key, dev);
233 neigh_release(n);
234 if (IS_ERR(mn))
235 return PTR_ERR(mn);
236 n = mn;
237 }
238
239 if (neigh_event_send(n, skb_res) == 0) {
240 int err;
241 char haddr[MAX_ADDR_LEN];
242
243 neigh_ha_snapshot(haddr, n, dev);
244 err = dev_hard_header(skb, dev, ntohs(skb_protocol(skb, false)),
245 haddr, NULL, skb->len);
246
247 if (err < 0)
248 err = -EINVAL;
249 } else {
250 err = (skb_res == NULL) ? -EAGAIN : 1;
251 }
252 neigh_release(n);
253 return err;
254}
255
256static inline int teql_resolve(struct sk_buff *skb,
257 struct sk_buff *skb_res,
258 struct net_device *dev,
259 struct netdev_queue *txq)
260{
261 struct dst_entry *dst = skb_dst(skb);
262 int res;
263
264 if (rcu_access_pointer(txq->qdisc) == &noop_qdisc)
265 return -ENODEV;
266
267 if (!dev->header_ops || !dst)
268 return 0;
269
270 rcu_read_lock();
271 res = __teql_resolve(skb, skb_res, dev, txq, dst);
272 rcu_read_unlock();
273
274 return res;
275}
276
277static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
278{
279 struct teql_master *master = netdev_priv(dev);
280 struct Qdisc *start, *q;
281 int busy;
282 int nores;
283 int subq = skb_get_queue_mapping(skb);
284 struct sk_buff *skb_res = NULL;
285
286 start = master->slaves;
287
288restart:
289 nores = 0;
290 busy = 0;
291
292 q = start;
293 if (!q)
294 goto drop;
295
296 do {
297 struct net_device *slave = qdisc_dev(q);
298 struct netdev_queue *slave_txq = netdev_get_tx_queue(slave, 0);
299
300 if (rcu_access_pointer(slave_txq->qdisc_sleeping) != q)
301 continue;
302 if (netif_xmit_stopped(netdev_get_tx_queue(slave, subq)) ||
303 !netif_running(slave)) {
304 busy = 1;
305 continue;
306 }
307
308 switch (teql_resolve(skb, skb_res, slave, slave_txq)) {
309 case 0:
310 if (__netif_tx_trylock(slave_txq)) {
311 unsigned int length = qdisc_pkt_len(skb);
312
313 if (!netif_xmit_frozen_or_stopped(slave_txq) &&
314 netdev_start_xmit(skb, slave, slave_txq, false) ==
315 NETDEV_TX_OK) {
316 __netif_tx_unlock(slave_txq);
317 master->slaves = NEXT_SLAVE(q);
318 netif_wake_queue(dev);
319 master->tx_packets++;
320 master->tx_bytes += length;
321 return NETDEV_TX_OK;
322 }
323 __netif_tx_unlock(slave_txq);
324 }
325 if (netif_xmit_stopped(netdev_get_tx_queue(dev, 0)))
326 busy = 1;
327 break;
328 case 1:
329 master->slaves = NEXT_SLAVE(q);
330 return NETDEV_TX_OK;
331 default:
332 nores = 1;
333 break;
334 }
335 __skb_pull(skb, skb_network_offset(skb));
336 } while ((q = NEXT_SLAVE(q)) != start);
337
338 if (nores && skb_res == NULL) {
339 skb_res = skb;
340 goto restart;
341 }
342
343 if (busy) {
344 netif_stop_queue(dev);
345 return NETDEV_TX_BUSY;
346 }
347 master->tx_errors++;
348
349drop:
350 master->tx_dropped++;
351 dev_kfree_skb(skb);
352 return NETDEV_TX_OK;
353}
354
355static int teql_master_open(struct net_device *dev)
356{
357 struct Qdisc *q;
358 struct teql_master *m = netdev_priv(dev);
359 int mtu = 0xFFFE;
360 unsigned int flags = IFF_NOARP | IFF_MULTICAST;
361
362 if (m->slaves == NULL)
363 return -EUNATCH;
364
365 flags = FMASK;
366
367 q = m->slaves;
368 do {
369 struct net_device *slave = qdisc_dev(q);
370
371 if (slave == NULL)
372 return -EUNATCH;
373
374 if (slave->mtu < mtu)
375 mtu = slave->mtu;
376 if (slave->hard_header_len > LL_MAX_HEADER)
377 return -EINVAL;
378
379 /* If all the slaves are BROADCAST, master is BROADCAST
380 If all the slaves are PtP, master is PtP
381 Otherwise, master is NBMA.
382 */
383 if (!(slave->flags&IFF_POINTOPOINT))
384 flags &= ~IFF_POINTOPOINT;
385 if (!(slave->flags&IFF_BROADCAST))
386 flags &= ~IFF_BROADCAST;
387 if (!(slave->flags&IFF_MULTICAST))
388 flags &= ~IFF_MULTICAST;
389 } while ((q = NEXT_SLAVE(q)) != m->slaves);
390
391 m->dev->mtu = mtu;
392 m->dev->flags = (m->dev->flags&~FMASK) | flags;
393 netif_start_queue(m->dev);
394 return 0;
395}
396
397static int teql_master_close(struct net_device *dev)
398{
399 netif_stop_queue(dev);
400 return 0;
401}
402
403static void teql_master_stats64(struct net_device *dev,
404 struct rtnl_link_stats64 *stats)
405{
406 struct teql_master *m = netdev_priv(dev);
407
408 stats->tx_packets = m->tx_packets;
409 stats->tx_bytes = m->tx_bytes;
410 stats->tx_errors = m->tx_errors;
411 stats->tx_dropped = m->tx_dropped;
412}
413
414static int teql_master_mtu(struct net_device *dev, int new_mtu)
415{
416 struct teql_master *m = netdev_priv(dev);
417 struct Qdisc *q;
418
419 q = m->slaves;
420 if (q) {
421 do {
422 if (new_mtu > qdisc_dev(q)->mtu)
423 return -EINVAL;
424 } while ((q = NEXT_SLAVE(q)) != m->slaves);
425 }
426
427 WRITE_ONCE(dev->mtu, new_mtu);
428 return 0;
429}
430
431static const struct net_device_ops teql_netdev_ops = {
432 .ndo_open = teql_master_open,
433 .ndo_stop = teql_master_close,
434 .ndo_start_xmit = teql_master_xmit,
435 .ndo_get_stats64 = teql_master_stats64,
436 .ndo_change_mtu = teql_master_mtu,
437};
438
439static __init void teql_master_setup(struct net_device *dev)
440{
441 struct teql_master *master = netdev_priv(dev);
442 struct Qdisc_ops *ops = &master->qops;
443
444 master->dev = dev;
445 ops->priv_size = sizeof(struct teql_sched_data);
446
447 ops->enqueue = teql_enqueue;
448 ops->dequeue = teql_dequeue;
449 ops->peek = teql_peek;
450 ops->init = teql_qdisc_init;
451 ops->reset = teql_reset;
452 ops->destroy = teql_destroy;
453 ops->owner = THIS_MODULE;
454
455 dev->netdev_ops = &teql_netdev_ops;
456 dev->type = ARPHRD_VOID;
457 dev->mtu = 1500;
458 dev->min_mtu = 68;
459 dev->max_mtu = 65535;
460 dev->tx_queue_len = 100;
461 dev->flags = IFF_NOARP;
462 dev->hard_header_len = LL_MAX_HEADER;
463 netif_keep_dst(dev);
464}
465
466static LIST_HEAD(master_dev_list);
467static int max_equalizers = 1;
468module_param(max_equalizers, int, 0);
469MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers");
470
471static int __init teql_init(void)
472{
473 int i;
474 int err = -ENODEV;
475
476 for (i = 0; i < max_equalizers; i++) {
477 struct net_device *dev;
478 struct teql_master *master;
479
480 dev = alloc_netdev(sizeof(struct teql_master), "teql%d",
481 NET_NAME_UNKNOWN, teql_master_setup);
482 if (!dev) {
483 err = -ENOMEM;
484 break;
485 }
486
487 if ((err = register_netdev(dev))) {
488 free_netdev(dev);
489 break;
490 }
491
492 master = netdev_priv(dev);
493
494 strscpy(master->qops.id, dev->name, IFNAMSIZ);
495 err = register_qdisc(&master->qops);
496
497 if (err) {
498 unregister_netdev(dev);
499 free_netdev(dev);
500 break;
501 }
502
503 list_add_tail(&master->master_list, &master_dev_list);
504 }
505 return i ? 0 : err;
506}
507
508static void __exit teql_exit(void)
509{
510 struct teql_master *master, *nxt;
511
512 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) {
513
514 list_del(&master->master_list);
515
516 unregister_qdisc(&master->qops);
517 unregister_netdev(master->dev);
518 free_netdev(master->dev);
519 }
520}
521
522module_init(teql_init);
523module_exit(teql_exit);
524
525MODULE_LICENSE("GPL");
526MODULE_DESCRIPTION("True (or trivial) link equalizer qdisc");