1 /* 2 * net/sched/cls_api.c Packet classifier API. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 10 * 11 * Changes: 12 * 13 * Eduardo J. Blanco <ejbs@netlabs.com.uy> :990222: kmod support 14 * 15 */ 16 17 #include <linux/module.h> 18 #include <linux/types.h> 19 #include <linux/kernel.h> 20 #include <linux/string.h> 21 #include <linux/errno.h> 22 #include <linux/skbuff.h> 23 #include <linux/init.h> 24 #include <linux/kmod.h> 25 #include <linux/netlink.h> 26 #include <linux/err.h> 27 #include <net/net_namespace.h> 28 #include <net/sock.h> 29 #include <net/netlink.h> 30 #include <net/pkt_sched.h> 31 #include <net/pkt_cls.h> 32 33 /* The list of all installed classifier types */ 34 35 static struct tcf_proto_ops *tcf_proto_base __read_mostly; 36 37 /* Protects list of registered TC modules. It is pure SMP lock. */ 38 static DEFINE_RWLOCK(cls_mod_lock); 39 40 /* Find classifier type by string name */ 41 42 static struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind) 43 { 44 struct tcf_proto_ops *t = NULL; 45 46 if (kind) { 47 read_lock(&cls_mod_lock); 48 for (t = tcf_proto_base; t; t = t->next) { 49 if (nla_strcmp(kind, t->kind) == 0) { 50 if (!try_module_get(t->owner)) 51 t = NULL; 52 break; 53 } 54 } 55 read_unlock(&cls_mod_lock); 56 } 57 return t; 58 } 59 60 /* Register(unregister) new classifier type */ 61 62 int register_tcf_proto_ops(struct tcf_proto_ops *ops) 63 { 64 struct tcf_proto_ops *t, **tp; 65 int rc = -EEXIST; 66 67 write_lock(&cls_mod_lock); 68 for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next) 69 if (!strcmp(ops->kind, t->kind)) 70 goto out; 71 72 ops->next = NULL; 73 *tp = ops; 74 rc = 0; 75 out: 76 write_unlock(&cls_mod_lock); 77 return rc; 78 } 79 EXPORT_SYMBOL(register_tcf_proto_ops); 80 81 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops) 82 { 83 struct tcf_proto_ops *t, **tp; 84 int rc = -ENOENT; 85 86 write_lock(&cls_mod_lock); 87 for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next) 88 if (t == ops) 89 break; 90 91 if (!t) 92 goto out; 93 *tp = t->next; 94 rc = 0; 95 out: 96 write_unlock(&cls_mod_lock); 97 return rc; 98 } 99 EXPORT_SYMBOL(unregister_tcf_proto_ops); 100 101 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n, 102 struct tcf_proto *tp, unsigned long fh, int event); 103 104 105 /* Select new prio value from the range, managed by kernel. */ 106 107 static inline u32 tcf_auto_prio(struct tcf_proto *tp) 108 { 109 u32 first = TC_H_MAKE(0xC0000000U, 0U); 110 111 if (tp) 112 first = tp->prio-1; 113 114 return first; 115 } 116 117 /* Add/change/delete/get a filter node */ 118 119 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg) 120 { 121 struct net *net = sock_net(skb->sk); 122 struct nlattr *tca[TCA_MAX + 1]; 123 spinlock_t *root_lock; 124 struct tcmsg *t; 125 u32 protocol; 126 u32 prio; 127 u32 nprio; 128 u32 parent; 129 struct net_device *dev; 130 struct Qdisc *q; 131 struct tcf_proto **back, **chain; 132 struct tcf_proto *tp; 133 struct tcf_proto_ops *tp_ops; 134 const struct Qdisc_class_ops *cops; 135 unsigned long cl; 136 unsigned long fh; 137 int err; 138 int tp_created = 0; 139 140 if (net != &init_net) 141 return -EINVAL; 142 143 replay: 144 t = NLMSG_DATA(n); 145 protocol = TC_H_MIN(t->tcm_info); 146 prio = TC_H_MAJ(t->tcm_info); 147 nprio = prio; 148 parent = t->tcm_parent; 149 cl = 0; 150 151 if (prio == 0) { 152 /* If no priority is given, user wants we allocated it. */ 153 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE)) 154 return -ENOENT; 155 prio = TC_H_MAKE(0x80000000U, 0U); 156 } 157 158 /* Find head of filter chain. */ 159 160 /* Find link */ 161 dev = __dev_get_by_index(&init_net, t->tcm_ifindex); 162 if (dev == NULL) 163 return -ENODEV; 164 165 err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL); 166 if (err < 0) 167 return err; 168 169 /* Find qdisc */ 170 if (!parent) { 171 struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, 0); 172 q = dev_queue->qdisc_sleeping; 173 parent = q->handle; 174 } else { 175 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent)); 176 if (q == NULL) 177 return -EINVAL; 178 } 179 180 /* Is it classful? */ 181 if ((cops = q->ops->cl_ops) == NULL) 182 return -EINVAL; 183 184 /* Do we search for filter, attached to class? */ 185 if (TC_H_MIN(parent)) { 186 cl = cops->get(q, parent); 187 if (cl == 0) 188 return -ENOENT; 189 } 190 191 /* And the last stroke */ 192 chain = cops->tcf_chain(q, cl); 193 err = -EINVAL; 194 if (chain == NULL) 195 goto errout; 196 197 /* Check the chain for existence of proto-tcf with this priority */ 198 for (back = chain; (tp=*back) != NULL; back = &tp->next) { 199 if (tp->prio >= prio) { 200 if (tp->prio == prio) { 201 if (!nprio || (tp->protocol != protocol && protocol)) 202 goto errout; 203 } else 204 tp = NULL; 205 break; 206 } 207 } 208 209 root_lock = qdisc_root_sleeping_lock(q); 210 211 if (tp == NULL) { 212 /* Proto-tcf does not exist, create new one */ 213 214 if (tca[TCA_KIND] == NULL || !protocol) 215 goto errout; 216 217 err = -ENOENT; 218 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE)) 219 goto errout; 220 221 222 /* Create new proto tcf */ 223 224 err = -ENOBUFS; 225 tp = kzalloc(sizeof(*tp), GFP_KERNEL); 226 if (tp == NULL) 227 goto errout; 228 err = -ENOENT; 229 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]); 230 if (tp_ops == NULL) { 231 #ifdef CONFIG_MODULES 232 struct nlattr *kind = tca[TCA_KIND]; 233 char name[IFNAMSIZ]; 234 235 if (kind != NULL && 236 nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) { 237 rtnl_unlock(); 238 request_module("cls_%s", name); 239 rtnl_lock(); 240 tp_ops = tcf_proto_lookup_ops(kind); 241 /* We dropped the RTNL semaphore in order to 242 * perform the module load. So, even if we 243 * succeeded in loading the module we have to 244 * replay the request. We indicate this using 245 * -EAGAIN. 246 */ 247 if (tp_ops != NULL) { 248 module_put(tp_ops->owner); 249 err = -EAGAIN; 250 } 251 } 252 #endif 253 kfree(tp); 254 goto errout; 255 } 256 tp->ops = tp_ops; 257 tp->protocol = protocol; 258 tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*back)); 259 tp->q = q; 260 tp->classify = tp_ops->classify; 261 tp->classid = parent; 262 263 err = tp_ops->init(tp); 264 if (err != 0) { 265 module_put(tp_ops->owner); 266 kfree(tp); 267 goto errout; 268 } 269 270 tp_created = 1; 271 272 } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) 273 goto errout; 274 275 fh = tp->ops->get(tp, t->tcm_handle); 276 277 if (fh == 0) { 278 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) { 279 spin_lock_bh(root_lock); 280 *back = tp->next; 281 spin_unlock_bh(root_lock); 282 283 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER); 284 tcf_destroy(tp); 285 err = 0; 286 goto errout; 287 } 288 289 err = -ENOENT; 290 if (n->nlmsg_type != RTM_NEWTFILTER || 291 !(n->nlmsg_flags & NLM_F_CREATE)) 292 goto errout; 293 } else { 294 switch (n->nlmsg_type) { 295 case RTM_NEWTFILTER: 296 err = -EEXIST; 297 if (n->nlmsg_flags & NLM_F_EXCL) { 298 if (tp_created) 299 tcf_destroy(tp); 300 goto errout; 301 } 302 break; 303 case RTM_DELTFILTER: 304 err = tp->ops->delete(tp, fh); 305 if (err == 0) 306 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER); 307 goto errout; 308 case RTM_GETTFILTER: 309 err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER); 310 goto errout; 311 default: 312 err = -EINVAL; 313 goto errout; 314 } 315 } 316 317 err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh); 318 if (err == 0) { 319 if (tp_created) { 320 spin_lock_bh(root_lock); 321 tp->next = *back; 322 *back = tp; 323 spin_unlock_bh(root_lock); 324 } 325 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER); 326 } else { 327 if (tp_created) 328 tcf_destroy(tp); 329 } 330 331 errout: 332 if (cl) 333 cops->put(q, cl); 334 if (err == -EAGAIN) 335 /* Replay the request. */ 336 goto replay; 337 return err; 338 } 339 340 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp, 341 unsigned long fh, u32 pid, u32 seq, u16 flags, int event) 342 { 343 struct tcmsg *tcm; 344 struct nlmsghdr *nlh; 345 unsigned char *b = skb_tail_pointer(skb); 346 347 nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags); 348 tcm = NLMSG_DATA(nlh); 349 tcm->tcm_family = AF_UNSPEC; 350 tcm->tcm__pad1 = 0; 351 tcm->tcm__pad1 = 0; 352 tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex; 353 tcm->tcm_parent = tp->classid; 354 tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol); 355 NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind); 356 tcm->tcm_handle = fh; 357 if (RTM_DELTFILTER != event) { 358 tcm->tcm_handle = 0; 359 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0) 360 goto nla_put_failure; 361 } 362 nlh->nlmsg_len = skb_tail_pointer(skb) - b; 363 return skb->len; 364 365 nlmsg_failure: 366 nla_put_failure: 367 nlmsg_trim(skb, b); 368 return -1; 369 } 370 371 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n, 372 struct tcf_proto *tp, unsigned long fh, int event) 373 { 374 struct sk_buff *skb; 375 u32 pid = oskb ? NETLINK_CB(oskb).pid : 0; 376 377 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 378 if (!skb) 379 return -ENOBUFS; 380 381 if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) { 382 kfree_skb(skb); 383 return -EINVAL; 384 } 385 386 return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC, 387 n->nlmsg_flags & NLM_F_ECHO); 388 } 389 390 struct tcf_dump_args { 391 struct tcf_walker w; 392 struct sk_buff *skb; 393 struct netlink_callback *cb; 394 }; 395 396 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, 397 struct tcf_walker *arg) 398 { 399 struct tcf_dump_args *a = (void *)arg; 400 401 return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid, 402 a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER); 403 } 404 405 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) 406 { 407 struct net *net = sock_net(skb->sk); 408 struct netdev_queue *dev_queue; 409 int t; 410 int s_t; 411 struct net_device *dev; 412 struct Qdisc *q; 413 struct tcf_proto *tp, **chain; 414 struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh); 415 unsigned long cl = 0; 416 const struct Qdisc_class_ops *cops; 417 struct tcf_dump_args arg; 418 419 if (net != &init_net) 420 return 0; 421 422 if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm))) 423 return skb->len; 424 if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL) 425 return skb->len; 426 427 dev_queue = netdev_get_tx_queue(dev, 0); 428 if (!tcm->tcm_parent) 429 q = dev_queue->qdisc_sleeping; 430 else 431 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent)); 432 if (!q) 433 goto out; 434 if ((cops = q->ops->cl_ops) == NULL) 435 goto errout; 436 if (TC_H_MIN(tcm->tcm_parent)) { 437 cl = cops->get(q, tcm->tcm_parent); 438 if (cl == 0) 439 goto errout; 440 } 441 chain = cops->tcf_chain(q, cl); 442 if (chain == NULL) 443 goto errout; 444 445 s_t = cb->args[0]; 446 447 for (tp=*chain, t=0; tp; tp = tp->next, t++) { 448 if (t < s_t) continue; 449 if (TC_H_MAJ(tcm->tcm_info) && 450 TC_H_MAJ(tcm->tcm_info) != tp->prio) 451 continue; 452 if (TC_H_MIN(tcm->tcm_info) && 453 TC_H_MIN(tcm->tcm_info) != tp->protocol) 454 continue; 455 if (t > s_t) 456 memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0])); 457 if (cb->args[1] == 0) { 458 if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid, 459 cb->nlh->nlmsg_seq, NLM_F_MULTI, 460 RTM_NEWTFILTER) <= 0) 461 break; 462 463 cb->args[1] = 1; 464 } 465 if (tp->ops->walk == NULL) 466 continue; 467 arg.w.fn = tcf_node_dump; 468 arg.skb = skb; 469 arg.cb = cb; 470 arg.w.stop = 0; 471 arg.w.skip = cb->args[1]-1; 472 arg.w.count = 0; 473 tp->ops->walk(tp, &arg.w); 474 cb->args[1] = arg.w.count+1; 475 if (arg.w.stop) 476 break; 477 } 478 479 cb->args[0] = t; 480 481 errout: 482 if (cl) 483 cops->put(q, cl); 484 out: 485 dev_put(dev); 486 return skb->len; 487 } 488 489 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts) 490 { 491 #ifdef CONFIG_NET_CLS_ACT 492 if (exts->action) { 493 tcf_action_destroy(exts->action, TCA_ACT_UNBIND); 494 exts->action = NULL; 495 } 496 #endif 497 } 498 EXPORT_SYMBOL(tcf_exts_destroy); 499 500 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb, 501 struct nlattr *rate_tlv, struct tcf_exts *exts, 502 const struct tcf_ext_map *map) 503 { 504 memset(exts, 0, sizeof(*exts)); 505 506 #ifdef CONFIG_NET_CLS_ACT 507 { 508 struct tc_action *act; 509 510 if (map->police && tb[map->police]) { 511 act = tcf_action_init_1(tb[map->police], rate_tlv, 512 "police", TCA_ACT_NOREPLACE, 513 TCA_ACT_BIND); 514 if (IS_ERR(act)) 515 return PTR_ERR(act); 516 517 act->type = TCA_OLD_COMPAT; 518 exts->action = act; 519 } else if (map->action && tb[map->action]) { 520 act = tcf_action_init(tb[map->action], rate_tlv, NULL, 521 TCA_ACT_NOREPLACE, TCA_ACT_BIND); 522 if (IS_ERR(act)) 523 return PTR_ERR(act); 524 525 exts->action = act; 526 } 527 } 528 #else 529 if ((map->action && tb[map->action]) || 530 (map->police && tb[map->police])) 531 return -EOPNOTSUPP; 532 #endif 533 534 return 0; 535 } 536 EXPORT_SYMBOL(tcf_exts_validate); 537 538 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst, 539 struct tcf_exts *src) 540 { 541 #ifdef CONFIG_NET_CLS_ACT 542 if (src->action) { 543 struct tc_action *act; 544 tcf_tree_lock(tp); 545 act = dst->action; 546 dst->action = src->action; 547 tcf_tree_unlock(tp); 548 if (act) 549 tcf_action_destroy(act, TCA_ACT_UNBIND); 550 } 551 #endif 552 } 553 EXPORT_SYMBOL(tcf_exts_change); 554 555 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts, 556 const struct tcf_ext_map *map) 557 { 558 #ifdef CONFIG_NET_CLS_ACT 559 if (map->action && exts->action) { 560 /* 561 * again for backward compatible mode - we want 562 * to work with both old and new modes of entering 563 * tc data even if iproute2 was newer - jhs 564 */ 565 struct nlattr *nest; 566 567 if (exts->action->type != TCA_OLD_COMPAT) { 568 nest = nla_nest_start(skb, map->action); 569 if (nest == NULL) 570 goto nla_put_failure; 571 if (tcf_action_dump(skb, exts->action, 0, 0) < 0) 572 goto nla_put_failure; 573 nla_nest_end(skb, nest); 574 } else if (map->police) { 575 nest = nla_nest_start(skb, map->police); 576 if (nest == NULL) 577 goto nla_put_failure; 578 if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0) 579 goto nla_put_failure; 580 nla_nest_end(skb, nest); 581 } 582 } 583 #endif 584 return 0; 585 nla_put_failure: __attribute__ ((unused)) 586 return -1; 587 } 588 EXPORT_SYMBOL(tcf_exts_dump); 589 590 591 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts, 592 const struct tcf_ext_map *map) 593 { 594 #ifdef CONFIG_NET_CLS_ACT 595 if (exts->action) 596 if (tcf_action_copy_stats(skb, exts->action, 1) < 0) 597 goto nla_put_failure; 598 #endif 599 return 0; 600 nla_put_failure: __attribute__ ((unused)) 601 return -1; 602 } 603 EXPORT_SYMBOL(tcf_exts_dump_stats); 604 605 static int __init tc_filter_init(void) 606 { 607 rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL); 608 rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL); 609 rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter, 610 tc_dump_tfilter); 611 612 return 0; 613 } 614 615 subsys_initcall(tc_filter_init); 616