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
;
100 skb
= __skb_dequeue(&dat
->q
);
101 dat_queue
= netdev_get_tx_queue(dat
->m
->dev
, 0);
103 struct net_device
*m
= qdisc_dev(dat_queue
->qdisc
);
105 dat
->m
->slaves
= sch
;
109 qdisc_bstats_update(sch
, skb
);
111 sch
->q
.qlen
= dat
->q
.qlen
+ dat_queue
->qdisc
->q
.qlen
;
115 static struct sk_buff
*
116 teql_peek(struct Qdisc
*sch
)
118 /* teql is meant to be used as root qdisc */
123 teql_neigh_release(struct neighbour
*n
)
130 teql_reset(struct Qdisc
*sch
)
132 struct teql_sched_data
*dat
= qdisc_priv(sch
);
134 skb_queue_purge(&dat
->q
);
139 teql_destroy(struct Qdisc
*sch
)
141 struct Qdisc
*q
, *prev
;
142 struct teql_sched_data
*dat
= qdisc_priv(sch
);
143 struct teql_master
*master
= dat
->m
;
145 prev
= master
->slaves
;
148 q
= NEXT_SLAVE(prev
);
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
;
157 txq
= netdev_get_tx_queue(master
->dev
, 0);
158 master
->slaves
= NULL
;
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
);
166 skb_queue_purge(&dat
->q
);
170 } while ((prev
= q
) != master
->slaves
);
174 static int teql_qdisc_init(struct Qdisc
*sch
, struct nlattr
*opt
)
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
);
180 if (dev
->hard_header_len
> m
->dev
->hard_header_len
)
188 skb_queue_head_init(&q
->q
);
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
)
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
;
210 q
->next
= NEXT_SLAVE(m
->slaves
);
211 NEXT_SLAVE(m
->slaves
) = sch
;
215 m
->dev
->mtu
= dev
->mtu
;
216 m
->dev
->flags
= (m
->dev
->flags
&~FMASK
)|(dev
->flags
&FMASK
);
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
)
230 n
= dst_neigh_lookup_skb(dst
, skb
);
234 if (dst
->dev
!= dev
) {
235 struct neighbour
*mn
;
237 mn
= __neigh_lookup_errno(n
->tbl
, n
->primary_key
, dev
);
244 if (neigh_event_send(n
, skb_res
) == 0) {
246 char haddr
[MAX_ADDR_LEN
];
248 neigh_ha_snapshot(haddr
, n
, dev
);
249 err
= dev_hard_header(skb
, dev
, ntohs(skb
->protocol
), haddr
,
255 err
= (skb_res
== NULL
) ? -EAGAIN
: 1;
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
)
266 struct dst_entry
*dst
= skb_dst(skb
);
269 if (txq
->qdisc
== &noop_qdisc
)
272 if (!dev
->header_ops
|| !dst
)
276 res
= __teql_resolve(skb
, skb_res
, dev
, txq
, dst
);
282 static netdev_tx_t
teql_master_xmit(struct sk_buff
*skb
, struct net_device
*dev
)
284 struct teql_master
*master
= netdev_priv(dev
);
285 struct Qdisc
*start
, *q
;
288 int subq
= skb_get_queue_mapping(skb
);
289 struct sk_buff
*skb_res
= NULL
;
291 start
= master
->slaves
;
302 struct net_device
*slave
= qdisc_dev(q
);
303 struct netdev_queue
*slave_txq
= netdev_get_tx_queue(slave
, 0);
305 if (slave_txq
->qdisc_sleeping
!= q
)
307 if (netif_xmit_stopped(netdev_get_tx_queue(slave
, subq
)) ||
308 !netif_running(slave
)) {
313 switch (teql_resolve(skb
, skb_res
, slave
, slave_txq
)) {
315 if (__netif_tx_trylock(slave_txq
)) {
316 unsigned int length
= qdisc_pkt_len(skb
);
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
;
328 __netif_tx_unlock(slave_txq
);
330 if (netif_xmit_stopped(netdev_get_tx_queue(dev
, 0)))
334 master
->slaves
= NEXT_SLAVE(q
);
340 __skb_pull(skb
, skb_network_offset(skb
));
341 } while ((q
= NEXT_SLAVE(q
)) != start
);
343 if (nores
&& skb_res
== NULL
) {
349 netif_stop_queue(dev
);
350 return NETDEV_TX_BUSY
;
355 master
->tx_dropped
++;
360 static int teql_master_open(struct net_device
*dev
)
363 struct teql_master
*m
= netdev_priv(dev
);
365 unsigned int flags
= IFF_NOARP
| IFF_MULTICAST
;
367 if (m
->slaves
== NULL
)
374 struct net_device
*slave
= qdisc_dev(q
);
379 if (slave
->mtu
< mtu
)
381 if (slave
->hard_header_len
> LL_MAX_HEADER
)
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.
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
);
397 m
->dev
->flags
= (m
->dev
->flags
&~FMASK
) | flags
;
398 netif_start_queue(m
->dev
);
402 static int teql_master_close(struct net_device
*dev
)
404 netif_stop_queue(dev
);
408 static struct rtnl_link_stats64
*teql_master_stats64(struct net_device
*dev
,
409 struct rtnl_link_stats64
*stats
)
411 struct teql_master
*m
= netdev_priv(dev
);
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
;
420 static int teql_master_mtu(struct net_device
*dev
, int new_mtu
)
422 struct teql_master
*m
= netdev_priv(dev
);
431 if (new_mtu
> qdisc_dev(q
)->mtu
)
433 } while ((q
= NEXT_SLAVE(q
)) != m
->slaves
);
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
,
448 static __init
void teql_master_setup(struct net_device
*dev
)
450 struct teql_master
*master
= netdev_priv(dev
);
451 struct Qdisc_ops
*ops
= &master
->qops
;
454 ops
->priv_size
= sizeof(struct teql_sched_data
);
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
;
464 dev
->netdev_ops
= &teql_netdev_ops
;
465 dev
->type
= ARPHRD_VOID
;
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
;
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");
478 static int __init
teql_init(void)
483 for (i
= 0; i
< max_equalizers
; i
++) {
484 struct net_device
*dev
;
485 struct teql_master
*master
;
487 dev
= alloc_netdev(sizeof(struct teql_master
), "teql%d",
488 NET_NAME_UNKNOWN
, teql_master_setup
);
494 if ((err
= register_netdev(dev
))) {
499 master
= netdev_priv(dev
);
501 strlcpy(master
->qops
.id
, dev
->name
, IFNAMSIZ
);
502 err
= register_qdisc(&master
->qops
);
505 unregister_netdev(dev
);
510 list_add_tail(&master
->master_list
, &master_dev_list
);
515 static void __exit
teql_exit(void)
517 struct teql_master
*master
, *nxt
;
519 list_for_each_entry_safe(master
, nxt
, &master_dev_list
, master_list
) {
521 list_del(&master
->master_list
);
523 unregister_qdisc(&master
->qops
);
524 unregister_netdev(master
->dev
);
525 free_netdev(master
->dev
);
529 module_init(teql_init
);
530 module_exit(teql_exit
);
532 MODULE_LICENSE("GPL");