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 { 58 struct Qdisc_ops qops; 59 struct net_device *dev; 60 struct Qdisc *slaves; 61 struct list_head master_list; 62 unsigned long tx_bytes; 63 unsigned long tx_packets; 64 unsigned long tx_errors; 65 unsigned long tx_dropped; 66 }; 67 68 struct teql_sched_data 69 { 70 struct Qdisc *next; 71 struct teql_master *m; 72 struct neighbour *ncache; 73 struct sk_buff_head q; 74 }; 75 76 #define NEXT_SLAVE(q) (((struct teql_sched_data*)qdisc_priv(q))->next) 77 78 #define FMASK (IFF_BROADCAST|IFF_POINTOPOINT) 79 80 /* "teql*" qdisc routines */ 81 82 static int 83 teql_enqueue(struct sk_buff *skb, struct Qdisc* sch) 84 { 85 struct net_device *dev = qdisc_dev(sch); 86 struct teql_sched_data *q = qdisc_priv(sch); 87 88 if (q->q.qlen < dev->tx_queue_len) { 89 __skb_queue_tail(&q->q, skb); 90 qdisc_bstats_update(sch, skb); 91 return NET_XMIT_SUCCESS; 92 } 93 94 kfree_skb(skb); 95 sch->qstats.drops++; 96 return NET_XMIT_DROP; 97 } 98 99 static struct sk_buff * 100 teql_dequeue(struct Qdisc* sch) 101 { 102 struct teql_sched_data *dat = qdisc_priv(sch); 103 struct netdev_queue *dat_queue; 104 struct sk_buff *skb; 105 106 skb = __skb_dequeue(&dat->q); 107 dat_queue = netdev_get_tx_queue(dat->m->dev, 0); 108 if (skb == NULL) { 109 struct net_device *m = qdisc_dev(dat_queue->qdisc); 110 if (m) { 111 dat->m->slaves = sch; 112 netif_wake_queue(m); 113 } 114 } 115 sch->q.qlen = dat->q.qlen + dat_queue->qdisc->q.qlen; 116 return skb; 117 } 118 119 static struct sk_buff * 120 teql_peek(struct Qdisc* sch) 121 { 122 /* teql is meant to be used as root qdisc */ 123 return NULL; 124 } 125 126 static __inline__ void 127 teql_neigh_release(struct neighbour *n) 128 { 129 if (n) 130 neigh_release(n); 131 } 132 133 static void 134 teql_reset(struct Qdisc* sch) 135 { 136 struct teql_sched_data *dat = qdisc_priv(sch); 137 138 skb_queue_purge(&dat->q); 139 sch->q.qlen = 0; 140 teql_neigh_release(xchg(&dat->ncache, NULL)); 141 } 142 143 static void 144 teql_destroy(struct Qdisc* sch) 145 { 146 struct Qdisc *q, *prev; 147 struct teql_sched_data *dat = qdisc_priv(sch); 148 struct teql_master *master = dat->m; 149 150 if ((prev = master->slaves) != NULL) { 151 do { 152 q = NEXT_SLAVE(prev); 153 if (q == sch) { 154 NEXT_SLAVE(prev) = NEXT_SLAVE(q); 155 if (q == master->slaves) { 156 master->slaves = NEXT_SLAVE(q); 157 if (q == master->slaves) { 158 struct netdev_queue *txq; 159 spinlock_t *root_lock; 160 161 txq = netdev_get_tx_queue(master->dev, 0); 162 master->slaves = NULL; 163 164 root_lock = qdisc_root_sleeping_lock(txq->qdisc); 165 spin_lock_bh(root_lock); 166 qdisc_reset(txq->qdisc); 167 spin_unlock_bh(root_lock); 168 } 169 } 170 skb_queue_purge(&dat->q); 171 teql_neigh_release(xchg(&dat->ncache, NULL)); 172 break; 173 } 174 175 } while ((prev = q) != master->slaves); 176 } 177 } 178 179 static int teql_qdisc_init(struct Qdisc *sch, struct nlattr *opt) 180 { 181 struct net_device *dev = qdisc_dev(sch); 182 struct teql_master *m = (struct teql_master*)sch->ops; 183 struct teql_sched_data *q = qdisc_priv(sch); 184 185 if (dev->hard_header_len > m->dev->hard_header_len) 186 return -EINVAL; 187 188 if (m->dev == dev) 189 return -ELOOP; 190 191 q->m = m; 192 193 skb_queue_head_init(&q->q); 194 195 if (m->slaves) { 196 if (m->dev->flags & IFF_UP) { 197 if ((m->dev->flags & IFF_POINTOPOINT && 198 !(dev->flags & IFF_POINTOPOINT)) || 199 (m->dev->flags & IFF_BROADCAST && 200 !(dev->flags & IFF_BROADCAST)) || 201 (m->dev->flags & IFF_MULTICAST && 202 !(dev->flags & IFF_MULTICAST)) || 203 dev->mtu < m->dev->mtu) 204 return -EINVAL; 205 } else { 206 if (!(dev->flags&IFF_POINTOPOINT)) 207 m->dev->flags &= ~IFF_POINTOPOINT; 208 if (!(dev->flags&IFF_BROADCAST)) 209 m->dev->flags &= ~IFF_BROADCAST; 210 if (!(dev->flags&IFF_MULTICAST)) 211 m->dev->flags &= ~IFF_MULTICAST; 212 if (dev->mtu < m->dev->mtu) 213 m->dev->mtu = dev->mtu; 214 } 215 q->next = NEXT_SLAVE(m->slaves); 216 NEXT_SLAVE(m->slaves) = sch; 217 } else { 218 q->next = sch; 219 m->slaves = sch; 220 m->dev->mtu = dev->mtu; 221 m->dev->flags = (m->dev->flags&~FMASK)|(dev->flags&FMASK); 222 } 223 return 0; 224 } 225 226 227 static int 228 __teql_resolve(struct sk_buff *skb, struct sk_buff *skb_res, struct net_device *dev) 229 { 230 struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0); 231 struct teql_sched_data *q = qdisc_priv(dev_queue->qdisc); 232 struct neighbour *mn = skb_dst(skb)->neighbour; 233 struct neighbour *n = q->ncache; 234 235 if (mn->tbl == NULL) 236 return -EINVAL; 237 if (n && n->tbl == mn->tbl && 238 memcmp(n->primary_key, mn->primary_key, mn->tbl->key_len) == 0) { 239 atomic_inc(&n->refcnt); 240 } else { 241 n = __neigh_lookup_errno(mn->tbl, mn->primary_key, dev); 242 if (IS_ERR(n)) 243 return PTR_ERR(n); 244 } 245 if (neigh_event_send(n, skb_res) == 0) { 246 int err; 247 char haddr[MAX_ADDR_LEN]; 248 249 neigh_ha_snapshot(haddr, n, dev); 250 err = dev_hard_header(skb, dev, ntohs(skb->protocol), haddr, 251 NULL, skb->len); 252 253 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 teql_resolve(struct sk_buff *skb, 265 struct sk_buff *skb_res, struct net_device *dev) 266 { 267 struct netdev_queue *txq = netdev_get_tx_queue(dev, 0); 268 if (txq->qdisc == &noop_qdisc) 269 return -ENODEV; 270 271 if (dev->header_ops == NULL || 272 skb_dst(skb) == NULL || 273 skb_dst(skb)->neighbour == NULL) 274 return 0; 275 return __teql_resolve(skb, skb_res, dev); 276 } 277 278 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev) 279 { 280 struct teql_master *master = netdev_priv(dev); 281 struct Qdisc *start, *q; 282 int busy; 283 int nores; 284 int subq = skb_get_queue_mapping(skb); 285 struct sk_buff *skb_res = NULL; 286 287 start = master->slaves; 288 289 restart: 290 nores = 0; 291 busy = 0; 292 293 if ((q = start) == NULL) 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 const struct net_device_ops *slave_ops = slave->netdev_ops; 300 301 if (slave_txq->qdisc_sleeping != q) 302 continue; 303 if (__netif_subqueue_stopped(slave, subq) || 304 !netif_running(slave)) { 305 busy = 1; 306 continue; 307 } 308 309 switch (teql_resolve(skb, skb_res, slave)) { 310 case 0: 311 if (__netif_tx_trylock(slave_txq)) { 312 unsigned int length = qdisc_pkt_len(skb); 313 314 if (!netif_tx_queue_frozen_or_stopped(slave_txq) && 315 slave_ops->ndo_start_xmit(skb, slave) == NETDEV_TX_OK) { 316 txq_trans_update(slave_txq); 317 __netif_tx_unlock(slave_txq); 318 master->slaves = NEXT_SLAVE(q); 319 netif_wake_queue(dev); 320 master->tx_packets++; 321 master->tx_bytes += length; 322 return NETDEV_TX_OK; 323 } 324 __netif_tx_unlock(slave_txq); 325 } 326 if (netif_queue_stopped(dev)) 327 busy = 1; 328 break; 329 case 1: 330 master->slaves = NEXT_SLAVE(q); 331 return NETDEV_TX_OK; 332 default: 333 nores = 1; 334 break; 335 } 336 __skb_pull(skb, skb_network_offset(skb)); 337 } while ((q = NEXT_SLAVE(q)) != start); 338 339 if (nores && skb_res == NULL) { 340 skb_res = skb; 341 goto restart; 342 } 343 344 if (busy) { 345 netif_stop_queue(dev); 346 return NETDEV_TX_BUSY; 347 } 348 master->tx_errors++; 349 350 drop: 351 master->tx_dropped++; 352 dev_kfree_skb(skb); 353 return NETDEV_TX_OK; 354 } 355 356 static int teql_master_open(struct net_device *dev) 357 { 358 struct Qdisc * q; 359 struct teql_master *m = netdev_priv(dev); 360 int mtu = 0xFFFE; 361 unsigned flags = IFF_NOARP|IFF_MULTICAST; 362 363 if (m->slaves == NULL) 364 return -EUNATCH; 365 366 flags = FMASK; 367 368 q = m->slaves; 369 do { 370 struct net_device *slave = qdisc_dev(q); 371 372 if (slave == NULL) 373 return -EUNATCH; 374 375 if (slave->mtu < mtu) 376 mtu = slave->mtu; 377 if (slave->hard_header_len > LL_MAX_HEADER) 378 return -EINVAL; 379 380 /* If all the slaves are BROADCAST, master is BROADCAST 381 If all the slaves are PtP, master is PtP 382 Otherwise, master is NBMA. 383 */ 384 if (!(slave->flags&IFF_POINTOPOINT)) 385 flags &= ~IFF_POINTOPOINT; 386 if (!(slave->flags&IFF_BROADCAST)) 387 flags &= ~IFF_BROADCAST; 388 if (!(slave->flags&IFF_MULTICAST)) 389 flags &= ~IFF_MULTICAST; 390 } while ((q = NEXT_SLAVE(q)) != m->slaves); 391 392 m->dev->mtu = mtu; 393 m->dev->flags = (m->dev->flags&~FMASK) | flags; 394 netif_start_queue(m->dev); 395 return 0; 396 } 397 398 static int teql_master_close(struct net_device *dev) 399 { 400 netif_stop_queue(dev); 401 return 0; 402 } 403 404 static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev, 405 struct rtnl_link_stats64 *stats) 406 { 407 struct teql_master *m = netdev_priv(dev); 408 409 stats->tx_packets = m->tx_packets; 410 stats->tx_bytes = m->tx_bytes; 411 stats->tx_errors = m->tx_errors; 412 stats->tx_dropped = m->tx_dropped; 413 return stats; 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 if (new_mtu < 68) 422 return -EINVAL; 423 424 q = m->slaves; 425 if (q) { 426 do { 427 if (new_mtu > qdisc_dev(q)->mtu) 428 return -EINVAL; 429 } while ((q=NEXT_SLAVE(q)) != m->slaves); 430 } 431 432 dev->mtu = new_mtu; 433 return 0; 434 } 435 436 static const struct net_device_ops teql_netdev_ops = { 437 .ndo_open = teql_master_open, 438 .ndo_stop = teql_master_close, 439 .ndo_start_xmit = teql_master_xmit, 440 .ndo_get_stats64 = teql_master_stats64, 441 .ndo_change_mtu = teql_master_mtu, 442 }; 443 444 static __init void teql_master_setup(struct net_device *dev) 445 { 446 struct teql_master *master = netdev_priv(dev); 447 struct Qdisc_ops *ops = &master->qops; 448 449 master->dev = dev; 450 ops->priv_size = sizeof(struct teql_sched_data); 451 452 ops->enqueue = teql_enqueue; 453 ops->dequeue = teql_dequeue; 454 ops->peek = teql_peek; 455 ops->init = teql_qdisc_init; 456 ops->reset = teql_reset; 457 ops->destroy = teql_destroy; 458 ops->owner = THIS_MODULE; 459 460 dev->netdev_ops = &teql_netdev_ops; 461 dev->type = ARPHRD_VOID; 462 dev->mtu = 1500; 463 dev->tx_queue_len = 100; 464 dev->flags = IFF_NOARP; 465 dev->hard_header_len = LL_MAX_HEADER; 466 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; 467 } 468 469 static LIST_HEAD(master_dev_list); 470 static int max_equalizers = 1; 471 module_param(max_equalizers, int, 0); 472 MODULE_PARM_DESC(max_equalizers, "Max number of link equalizers"); 473 474 static int __init teql_init(void) 475 { 476 int i; 477 int err = -ENODEV; 478 479 for (i = 0; i < max_equalizers; i++) { 480 struct net_device *dev; 481 struct teql_master *master; 482 483 dev = alloc_netdev(sizeof(struct teql_master), 484 "teql%d", teql_master_setup); 485 if (!dev) { 486 err = -ENOMEM; 487 break; 488 } 489 490 if ((err = register_netdev(dev))) { 491 free_netdev(dev); 492 break; 493 } 494 495 master = netdev_priv(dev); 496 497 strlcpy(master->qops.id, dev->name, IFNAMSIZ); 498 err = register_qdisc(&master->qops); 499 500 if (err) { 501 unregister_netdev(dev); 502 free_netdev(dev); 503 break; 504 } 505 506 list_add_tail(&master->master_list, &master_dev_list); 507 } 508 return i ? 0 : err; 509 } 510 511 static void __exit teql_exit(void) 512 { 513 struct teql_master *master, *nxt; 514 515 list_for_each_entry_safe(master, nxt, &master_dev_list, master_list) { 516 517 list_del(&master->master_list); 518 519 unregister_qdisc(&master->qops); 520 unregister_netdev(master->dev); 521 free_netdev(master->dev); 522 } 523 } 524 525 module_init(teql_init); 526 module_exit(teql_exit); 527 528 MODULE_LICENSE("GPL"); 529