Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 <asm/uaccess.h> |
| 13 | #include <asm/system.h> |
| 14 | #include <linux/bitops.h> |
| 15 | #include <linux/types.h> |
| 16 | #include <linux/kernel.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/string.h> |
| 18 | #include <linux/mm.h> |
| 19 | #include <linux/socket.h> |
| 20 | #include <linux/sockios.h> |
| 21 | #include <linux/in.h> |
| 22 | #include <linux/errno.h> |
| 23 | #include <linux/interrupt.h> |
Arnaldo Carvalho de Melo | 14c8502 | 2005-12-27 02:43:12 -0200 | [diff] [blame] | 24 | #include <linux/if_arp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/if_ether.h> |
| 26 | #include <linux/inet.h> |
| 27 | #include <linux/netdevice.h> |
| 28 | #include <linux/etherdevice.h> |
| 29 | #include <linux/notifier.h> |
| 30 | #include <linux/init.h> |
| 31 | #include <net/ip.h> |
| 32 | #include <net/route.h> |
| 33 | #include <linux/skbuff.h> |
| 34 | #include <linux/moduleparam.h> |
| 35 | #include <net/sock.h> |
| 36 | #include <net/pkt_sched.h> |
| 37 | |
| 38 | /* |
| 39 | How to setup it. |
| 40 | ---------------- |
| 41 | |
| 42 | After loading this module you will find a new device teqlN |
| 43 | and new qdisc with the same name. To join a slave to the equalizer |
| 44 | you should just set this qdisc on a device f.e. |
| 45 | |
| 46 | # tc qdisc add dev eth0 root teql0 |
| 47 | # tc qdisc add dev eth1 root teql0 |
| 48 | |
| 49 | That's all. Full PnP 8) |
| 50 | |
| 51 | Applicability. |
| 52 | -------------- |
| 53 | |
| 54 | 1. Slave devices MUST be active devices, i.e., they must raise the tbusy |
| 55 | signal and generate EOI events. If you want to equalize virtual devices |
| 56 | like tunnels, use a normal eql device. |
| 57 | 2. This device puts no limitations on physical slave characteristics |
| 58 | f.e. it will equalize 9600baud line and 100Mb ethernet perfectly :-) |
| 59 | Certainly, large difference in link speeds will make the resulting |
| 60 | eqalized link unusable, because of huge packet reordering. |
| 61 | I estimate an upper useful difference as ~10 times. |
| 62 | 3. If the slave requires address resolution, only protocols using |
| 63 | neighbour cache (IPv4/IPv6) will work over the equalized link. |
| 64 | Other protocols are still allowed to use the slave device directly, |
| 65 | which will not break load balancing, though native slave |
| 66 | traffic will have the highest priority. */ |
| 67 | |
| 68 | struct teql_master |
| 69 | { |
| 70 | struct Qdisc_ops qops; |
| 71 | struct net_device *dev; |
| 72 | struct Qdisc *slaves; |
| 73 | struct list_head master_list; |
| 74 | struct net_device_stats stats; |
| 75 | }; |
| 76 | |
| 77 | struct teql_sched_data |
| 78 | { |
| 79 | struct Qdisc *next; |
| 80 | struct teql_master *m; |
| 81 | struct neighbour *ncache; |
| 82 | struct sk_buff_head q; |
| 83 | }; |
| 84 | |
| 85 | #define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next) |
| 86 | |
| 87 | #define FMASK (IFF_BROADCAST|IFF_POINTOPOINT|IFF_BROADCAST) |
| 88 | |
| 89 | /* "teql*" qdisc routines */ |
| 90 | |
| 91 | static int |
| 92 | teql_enqueue(struct sk_buff *skb, struct Qdisc* sch) |
| 93 | { |
| 94 | struct net_device *dev = sch->dev; |
| 95 | struct teql_sched_data *q = qdisc_priv(sch); |
| 96 | |
| 97 | __skb_queue_tail(&q->q, skb); |
| 98 | if (q->q.qlen <= dev->tx_queue_len) { |
| 99 | sch->bstats.bytes += skb->len; |
| 100 | sch->bstats.packets++; |
| 101 | return 0; |
| 102 | } |
| 103 | |
| 104 | __skb_unlink(skb, &q->q); |
| 105 | kfree_skb(skb); |
| 106 | sch->qstats.drops++; |
| 107 | return NET_XMIT_DROP; |
| 108 | } |
| 109 | |
| 110 | static int |
| 111 | teql_requeue(struct sk_buff *skb, struct Qdisc* sch) |
| 112 | { |
| 113 | struct teql_sched_data *q = qdisc_priv(sch); |
| 114 | |
| 115 | __skb_queue_head(&q->q, skb); |
| 116 | sch->qstats.requeues++; |
| 117 | return 0; |
| 118 | } |
| 119 | |
| 120 | static struct sk_buff * |
| 121 | teql_dequeue(struct Qdisc* sch) |
| 122 | { |
| 123 | struct teql_sched_data *dat = qdisc_priv(sch); |
| 124 | struct sk_buff *skb; |
| 125 | |
| 126 | skb = __skb_dequeue(&dat->q); |
| 127 | if (skb == NULL) { |
| 128 | struct net_device *m = dat->m->dev->qdisc->dev; |
| 129 | if (m) { |
| 130 | dat->m->slaves = sch; |
| 131 | netif_wake_queue(m); |
| 132 | } |
| 133 | } |
| 134 | sch->q.qlen = dat->q.qlen + dat->m->dev->qdisc->q.qlen; |
| 135 | return skb; |
| 136 | } |
| 137 | |
| 138 | static __inline__ void |
| 139 | teql_neigh_release(struct neighbour *n) |
| 140 | { |
| 141 | if (n) |
| 142 | neigh_release(n); |
| 143 | } |
| 144 | |
| 145 | static void |
| 146 | teql_reset(struct Qdisc* sch) |
| 147 | { |
| 148 | struct teql_sched_data *dat = qdisc_priv(sch); |
| 149 | |
| 150 | skb_queue_purge(&dat->q); |
| 151 | sch->q.qlen = 0; |
| 152 | teql_neigh_release(xchg(&dat->ncache, NULL)); |
| 153 | } |
| 154 | |
| 155 | static void |
| 156 | teql_destroy(struct Qdisc* sch) |
| 157 | { |
| 158 | struct Qdisc *q, *prev; |
| 159 | struct teql_sched_data *dat = qdisc_priv(sch); |
| 160 | struct teql_master *master = dat->m; |
| 161 | |
| 162 | if ((prev = master->slaves) != NULL) { |
| 163 | do { |
| 164 | q = NEXT_SLAVE(prev); |
| 165 | if (q == sch) { |
| 166 | NEXT_SLAVE(prev) = NEXT_SLAVE(q); |
| 167 | if (q == master->slaves) { |
| 168 | master->slaves = NEXT_SLAVE(q); |
| 169 | if (q == master->slaves) { |
| 170 | master->slaves = NULL; |
| 171 | spin_lock_bh(&master->dev->queue_lock); |
| 172 | qdisc_reset(master->dev->qdisc); |
| 173 | spin_unlock_bh(&master->dev->queue_lock); |
| 174 | } |
| 175 | } |
| 176 | skb_queue_purge(&dat->q); |
| 177 | teql_neigh_release(xchg(&dat->ncache, NULL)); |
| 178 | break; |
| 179 | } |
YOSHIFUJI Hideaki | 10297b9 | 2007-02-09 23:25:16 +0900 | [diff] [blame] | 180 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | } while ((prev = q) != master->slaves); |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | static int teql_qdisc_init(struct Qdisc *sch, struct rtattr *opt) |
| 186 | { |
| 187 | struct net_device *dev = sch->dev; |
| 188 | struct teql_master *m = (struct teql_master*)sch->ops; |
| 189 | struct teql_sched_data *q = qdisc_priv(sch); |
| 190 | |
| 191 | if (dev->hard_header_len > m->dev->hard_header_len) |
| 192 | return -EINVAL; |
| 193 | |
| 194 | if (m->dev == dev) |
| 195 | return -ELOOP; |
| 196 | |
| 197 | q->m = m; |
| 198 | |
| 199 | skb_queue_head_init(&q->q); |
| 200 | |
| 201 | if (m->slaves) { |
| 202 | if (m->dev->flags & IFF_UP) { |
| 203 | if ((m->dev->flags&IFF_POINTOPOINT && !(dev->flags&IFF_POINTOPOINT)) |
| 204 | || (m->dev->flags&IFF_BROADCAST && !(dev->flags&IFF_BROADCAST)) |
| 205 | || (m->dev->flags&IFF_MULTICAST && !(dev->flags&IFF_MULTICAST)) |
| 206 | || dev->mtu < m->dev->mtu) |
| 207 | return -EINVAL; |
| 208 | } else { |
| 209 | if (!(dev->flags&IFF_POINTOPOINT)) |
| 210 | m->dev->flags &= ~IFF_POINTOPOINT; |
| 211 | if (!(dev->flags&IFF_BROADCAST)) |
| 212 | m->dev->flags &= ~IFF_BROADCAST; |
| 213 | if (!(dev->flags&IFF_MULTICAST)) |
| 214 | m->dev->flags &= ~IFF_MULTICAST; |
| 215 | if (dev->mtu < m->dev->mtu) |
| 216 | m->dev->mtu = dev->mtu; |
| 217 | } |
| 218 | q->next = NEXT_SLAVE(m->slaves); |
| 219 | NEXT_SLAVE(m->slaves) = sch; |
| 220 | } else { |
| 221 | q->next = sch; |
| 222 | m->slaves = sch; |
| 223 | m->dev->mtu = dev->mtu; |
| 224 | m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK); |
| 225 | } |
| 226 | return 0; |
| 227 | } |
| 228 | |
| 229 | /* "teql*" netdevice routines */ |
| 230 | |
| 231 | static int |
| 232 | __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev) |
| 233 | { |
| 234 | struct teql_sched_data *q = qdisc_priv(dev->qdisc); |
| 235 | struct neighbour *mn = skb->dst->neighbour; |
| 236 | struct neighbour *n = q->ncache; |
| 237 | |
| 238 | if (mn->tbl == NULL) |
| 239 | return -EINVAL; |
| 240 | if (n && n->tbl == mn->tbl && |
| 241 | memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) { |
| 242 | atomic_inc(&n->refcnt); |
| 243 | } else { |
| 244 | n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev); |
| 245 | if (IS_ERR(n)) |
| 246 | return PTR_ERR(n); |
| 247 | } |
| 248 | if (neigh_event_send(n, skb_res) == 0) { |
| 249 | int err; |
| 250 | read_lock(&n->lock); |
| 251 | err = dev->hard_header(skb, dev, ntohs(skb->protocol), n->ha, NULL, skb->len); |
| 252 | read_unlock(&n->lock); |
| 253 | if (err < 0) { |
| 254 | neigh_release(n); |
| 255 | return -EINVAL; |
| 256 | } |
| 257 | teql_neigh_release(xchg(&q->ncache, n)); |
| 258 | return 0; |
| 259 | } |
| 260 | neigh_release(n); |
| 261 | return (skb_res == NULL) ? -EAGAIN : 1; |
| 262 | } |
| 263 | |
| 264 | static __inline__ int |
| 265 | teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev) |
| 266 | { |
| 267 | if (dev->hard_header == NULL || |
| 268 | skb->dst == NULL || |
| 269 | skb->dst->neighbour == NULL) |
| 270 | return 0; |
| 271 | return __teql_resolve(skb, skb_res, dev); |
| 272 | } |
| 273 | |
| 274 | static int teql_master_xmit(struct sk_buff *skb, struct net_device *dev) |
| 275 | { |
Patrick McHardy | 2941a48 | 2006-01-08 22:05:26 -0800 | [diff] [blame] | 276 | struct teql_master *master = netdev_priv(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | struct Qdisc *start, *q; |
| 278 | int busy; |
| 279 | int nores; |
| 280 | int len = skb->len; |
| 281 | struct sk_buff *skb_res = NULL; |
| 282 | |
| 283 | start = master->slaves; |
| 284 | |
| 285 | restart: |
| 286 | nores = 0; |
| 287 | busy = 0; |
| 288 | |
| 289 | if ((q = start) == NULL) |
| 290 | goto drop; |
| 291 | |
| 292 | do { |
| 293 | struct net_device *slave = q->dev; |
YOSHIFUJI Hideaki | 10297b9 | 2007-02-09 23:25:16 +0900 | [diff] [blame] | 294 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 295 | if (slave->qdisc_sleeping != q) |
| 296 | continue; |
| 297 | if (netif_queue_stopped(slave) || ! netif_running(slave)) { |
| 298 | busy = 1; |
| 299 | continue; |
| 300 | } |
| 301 | |
| 302 | switch (teql_resolve(skb, skb_res, slave)) { |
| 303 | case 0: |
Herbert Xu | 932ff27 | 2006-06-09 12:20:56 -0700 | [diff] [blame] | 304 | if (netif_tx_trylock(slave)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | if (!netif_queue_stopped(slave) && |
| 306 | slave->hard_start_xmit(skb, slave) == 0) { |
Herbert Xu | 932ff27 | 2006-06-09 12:20:56 -0700 | [diff] [blame] | 307 | netif_tx_unlock(slave); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 308 | master->slaves = NEXT_SLAVE(q); |
| 309 | netif_wake_queue(dev); |
| 310 | master->stats.tx_packets++; |
| 311 | master->stats.tx_bytes += len; |
| 312 | return 0; |
| 313 | } |
Herbert Xu | 932ff27 | 2006-06-09 12:20:56 -0700 | [diff] [blame] | 314 | netif_tx_unlock(slave); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | } |
| 316 | if (netif_queue_stopped(dev)) |
| 317 | busy = 1; |
| 318 | break; |
| 319 | case 1: |
| 320 | master->slaves = NEXT_SLAVE(q); |
| 321 | return 0; |
| 322 | default: |
| 323 | nores = 1; |
| 324 | break; |
| 325 | } |
| 326 | __skb_pull(skb, skb->nh.raw - skb->data); |
| 327 | } while ((q = NEXT_SLAVE(q)) != start); |
| 328 | |
| 329 | if (nores && skb_res == NULL) { |
| 330 | skb_res = skb; |
| 331 | goto restart; |
| 332 | } |
| 333 | |
| 334 | if (busy) { |
| 335 | netif_stop_queue(dev); |
| 336 | return 1; |
| 337 | } |
| 338 | master->stats.tx_errors++; |
| 339 | |
| 340 | drop: |
| 341 | master->stats.tx_dropped++; |
| 342 | dev_kfree_skb(skb); |
| 343 | return 0; |
| 344 | } |
| 345 | |
| 346 | static int teql_master_open(struct net_device *dev) |
| 347 | { |
| 348 | struct Qdisc * q; |
Patrick McHardy | 2941a48 | 2006-01-08 22:05:26 -0800 | [diff] [blame] | 349 | struct teql_master *m = netdev_priv(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | int mtu = 0xFFFE; |
| 351 | unsigned flags = IFF_NOARP|IFF_MULTICAST; |
| 352 | |
| 353 | if (m->slaves == NULL) |
| 354 | return -EUNATCH; |
| 355 | |
| 356 | flags = FMASK; |
| 357 | |
| 358 | q = m->slaves; |
| 359 | do { |
| 360 | struct net_device *slave = q->dev; |
| 361 | |
| 362 | if (slave == NULL) |
| 363 | return -EUNATCH; |
| 364 | |
| 365 | if (slave->mtu < mtu) |
| 366 | mtu = slave->mtu; |
| 367 | if (slave->hard_header_len > LL_MAX_HEADER) |
| 368 | return -EINVAL; |
| 369 | |
| 370 | /* If all the slaves are BROADCAST, master is BROADCAST |
| 371 | If all the slaves are PtP, master is PtP |
| 372 | Otherwise, master is NBMA. |
| 373 | */ |
| 374 | if (!(slave->flags&IFF_POINTOPOINT)) |
| 375 | flags &= ~IFF_POINTOPOINT; |
| 376 | if (!(slave->flags&IFF_BROADCAST)) |
| 377 | flags &= ~IFF_BROADCAST; |
| 378 | if (!(slave->flags&IFF_MULTICAST)) |
| 379 | flags &= ~IFF_MULTICAST; |
| 380 | } while ((q = NEXT_SLAVE(q)) != m->slaves); |
| 381 | |
| 382 | m->dev->mtu = mtu; |
| 383 | m->dev->flags = (m->dev->flags&~FMASK) | flags; |
| 384 | netif_start_queue(m->dev); |
| 385 | return 0; |
| 386 | } |
| 387 | |
| 388 | static int teql_master_close(struct net_device *dev) |
| 389 | { |
| 390 | netif_stop_queue(dev); |
| 391 | return 0; |
| 392 | } |
| 393 | |
| 394 | static struct net_device_stats *teql_master_stats(struct net_device *dev) |
| 395 | { |
Patrick McHardy | 2941a48 | 2006-01-08 22:05:26 -0800 | [diff] [blame] | 396 | struct teql_master *m = netdev_priv(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 397 | return &m->stats; |
| 398 | } |
| 399 | |
| 400 | static int teql_master_mtu(struct net_device *dev, int new_mtu) |
| 401 | { |
Patrick McHardy | 2941a48 | 2006-01-08 22:05:26 -0800 | [diff] [blame] | 402 | struct teql_master *m = netdev_priv(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 403 | struct Qdisc *q; |
| 404 | |
| 405 | if (new_mtu < 68) |
| 406 | return -EINVAL; |
| 407 | |
| 408 | q = m->slaves; |
| 409 | if (q) { |
| 410 | do { |
| 411 | if (new_mtu > q->dev->mtu) |
| 412 | return -EINVAL; |
| 413 | } while ((q=NEXT_SLAVE(q)) != m->slaves); |
| 414 | } |
| 415 | |
| 416 | dev->mtu = new_mtu; |
| 417 | return 0; |
| 418 | } |
| 419 | |
| 420 | static __init void teql_master_setup(struct net_device *dev) |
| 421 | { |
Patrick McHardy | 2941a48 | 2006-01-08 22:05:26 -0800 | [diff] [blame] | 422 | struct teql_master *master = netdev_priv(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | struct Qdisc_ops *ops = &master->qops; |
| 424 | |
| 425 | master->dev = dev; |
| 426 | ops->priv_size = sizeof(struct teql_sched_data); |
YOSHIFUJI Hideaki | 10297b9 | 2007-02-09 23:25:16 +0900 | [diff] [blame] | 427 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | ops->enqueue = teql_enqueue; |
| 429 | ops->dequeue = teql_dequeue; |
| 430 | ops->requeue = teql_requeue; |
| 431 | ops->init = teql_qdisc_init; |
| 432 | ops->reset = teql_reset; |
| 433 | ops->destroy = teql_destroy; |
| 434 | ops->owner = THIS_MODULE; |
| 435 | |
| 436 | dev->open = teql_master_open; |
| 437 | dev->hard_start_xmit = teql_master_xmit; |
| 438 | dev->stop = teql_master_close; |
| 439 | dev->get_stats = teql_master_stats; |
| 440 | dev->change_mtu = teql_master_mtu; |
| 441 | dev->type = ARPHRD_VOID; |
| 442 | dev->mtu = 1500; |
| 443 | dev->tx_queue_len = 100; |
| 444 | dev->flags = IFF_NOARP; |
| 445 | dev->hard_header_len = LL_MAX_HEADER; |
| 446 | SET_MODULE_OWNER(dev); |
| 447 | } |
| 448 | |
| 449 | static LIST_HEAD(master_dev_list); |
| 450 | static int max_equalizers = 1; |
| 451 | module_param(max_equalizers, int, 0); |
| 452 | MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers"); |
| 453 | |
| 454 | static int __init teql_init(void) |
| 455 | { |
| 456 | int i; |
| 457 | int err = -ENODEV; |
| 458 | |
| 459 | for (i = 0; i < max_equalizers; i++) { |
| 460 | struct net_device *dev; |
| 461 | struct teql_master *master; |
| 462 | |
| 463 | dev = alloc_netdev(sizeof(struct teql_master), |
| 464 | "teql%d", teql_master_setup); |
| 465 | if (!dev) { |
| 466 | err = -ENOMEM; |
| 467 | break; |
| 468 | } |
| 469 | |
| 470 | if ((err = register_netdev(dev))) { |
| 471 | free_netdev(dev); |
| 472 | break; |
| 473 | } |
| 474 | |
Patrick McHardy | 2941a48 | 2006-01-08 22:05:26 -0800 | [diff] [blame] | 475 | master = netdev_priv(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 476 | |
| 477 | strlcpy(master->qops.id, dev->name, IFNAMSIZ); |
| 478 | err = register_qdisc(&master->qops); |
| 479 | |
| 480 | if (err) { |
| 481 | unregister_netdev(dev); |
| 482 | free_netdev(dev); |
| 483 | break; |
| 484 | } |
| 485 | |
| 486 | list_add_tail(&master->master_list, &master_dev_list); |
| 487 | } |
| 488 | return i ? 0 : err; |
| 489 | } |
| 490 | |
YOSHIFUJI Hideaki | 10297b9 | 2007-02-09 23:25:16 +0900 | [diff] [blame] | 491 | static void __exit teql_exit(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | { |
| 493 | struct teql_master *master, *nxt; |
| 494 | |
| 495 | list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) { |
| 496 | |
| 497 | list_del(&master->master_list); |
| 498 | |
| 499 | unregister_qdisc(&master->qops); |
| 500 | unregister_netdev(master->dev); |
| 501 | free_netdev(master->dev); |
| 502 | } |
| 503 | } |
| 504 | |
| 505 | module_init(teql_init); |
| 506 | module_exit(teql_exit); |
| 507 | |
| 508 | MODULE_LICENSE("GPL"); |