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/err.h> 26 #include <linux/slab.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 static LIST_HEAD(tcf_proto_base); 35 36 /* Protects list of registered TC modules. It is pure SMP lock. */ 37 static DEFINE_RWLOCK(cls_mod_lock); 38 39 /* Find classifier type by string name */ 40 41 static const struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind) 42 { 43 const struct tcf_proto_ops *t, *res = NULL; 44 45 if (kind) { 46 read_lock(&cls_mod_lock); 47 list_for_each_entry(t, &tcf_proto_base, head) { 48 if (nla_strcmp(kind, t->kind) == 0) { 49 if (try_module_get(t->owner)) 50 res = t; 51 break; 52 } 53 } 54 read_unlock(&cls_mod_lock); 55 } 56 return res; 57 } 58 59 /* Register(unregister) new classifier type */ 60 61 int register_tcf_proto_ops(struct tcf_proto_ops *ops) 62 { 63 struct tcf_proto_ops *t; 64 int rc = -EEXIST; 65 66 write_lock(&cls_mod_lock); 67 list_for_each_entry(t, &tcf_proto_base, head) 68 if (!strcmp(ops->kind, t->kind)) 69 goto out; 70 71 list_add_tail(&ops->head, &tcf_proto_base); 72 rc = 0; 73 out: 74 write_unlock(&cls_mod_lock); 75 return rc; 76 } 77 EXPORT_SYMBOL(register_tcf_proto_ops); 78 79 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops) 80 { 81 struct tcf_proto_ops *t; 82 int rc = -ENOENT; 83 84 /* Wait for outstanding call_rcu()s, if any, from a 85 * tcf_proto_ops's destroy() handler. 86 */ 87 rcu_barrier(); 88 89 write_lock(&cls_mod_lock); 90 list_for_each_entry(t, &tcf_proto_base, head) { 91 if (t == ops) { 92 list_del(&t->head); 93 rc = 0; 94 break; 95 } 96 } 97 write_unlock(&cls_mod_lock); 98 return rc; 99 } 100 EXPORT_SYMBOL(unregister_tcf_proto_ops); 101 102 static int tfilter_notify(struct net *net, struct sk_buff *oskb, 103 struct nlmsghdr *n, struct tcf_proto *tp, 104 unsigned long fh, int event, bool unicast); 105 106 static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb, 107 struct nlmsghdr *n, 108 struct tcf_proto __rcu **chain, int event) 109 { 110 struct tcf_proto __rcu **it_chain; 111 struct tcf_proto *tp; 112 113 for (it_chain = chain; (tp = rtnl_dereference(*it_chain)) != NULL; 114 it_chain = &tp->next) 115 tfilter_notify(net, oskb, n, tp, 0, event, false); 116 } 117 118 /* Select new prio value from the range, managed by kernel. */ 119 120 static inline u32 tcf_auto_prio(struct tcf_proto *tp) 121 { 122 u32 first = TC_H_MAKE(0xC0000000U, 0U); 123 124 if (tp) 125 first = tp->prio - 1; 126 127 return first; 128 } 129 130 /* Add/change/delete/get a filter node */ 131 132 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n) 133 { 134 struct net *net = sock_net(skb->sk); 135 struct nlattr *tca[TCA_MAX + 1]; 136 struct tcmsg *t; 137 u32 protocol; 138 u32 prio; 139 u32 nprio; 140 u32 parent; 141 struct net_device *dev; 142 struct Qdisc *q; 143 struct tcf_proto __rcu **back; 144 struct tcf_proto __rcu **chain; 145 struct tcf_proto *tp; 146 const struct tcf_proto_ops *tp_ops; 147 const struct Qdisc_class_ops *cops; 148 unsigned long cl; 149 unsigned long fh; 150 int err; 151 int tp_created; 152 153 if ((n->nlmsg_type != RTM_GETTFILTER) && 154 !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) 155 return -EPERM; 156 157 replay: 158 tp_created = 0; 159 160 err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL); 161 if (err < 0) 162 return err; 163 164 t = nlmsg_data(n); 165 protocol = TC_H_MIN(t->tcm_info); 166 prio = TC_H_MAJ(t->tcm_info); 167 nprio = prio; 168 parent = t->tcm_parent; 169 cl = 0; 170 171 if (prio == 0) { 172 switch (n->nlmsg_type) { 173 case RTM_DELTFILTER: 174 if (protocol || t->tcm_handle || tca[TCA_KIND]) 175 return -ENOENT; 176 break; 177 case RTM_NEWTFILTER: 178 /* If no priority is provided by the user, 179 * we allocate one. 180 */ 181 if (n->nlmsg_flags & NLM_F_CREATE) { 182 prio = TC_H_MAKE(0x80000000U, 0U); 183 break; 184 } 185 /* fall-through */ 186 default: 187 return -ENOENT; 188 } 189 } 190 191 /* Find head of filter chain. */ 192 193 /* Find link */ 194 dev = __dev_get_by_index(net, t->tcm_ifindex); 195 if (dev == NULL) 196 return -ENODEV; 197 198 /* Find qdisc */ 199 if (!parent) { 200 q = dev->qdisc; 201 parent = q->handle; 202 } else { 203 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent)); 204 if (q == NULL) 205 return -EINVAL; 206 } 207 208 /* Is it classful? */ 209 cops = q->ops->cl_ops; 210 if (!cops) 211 return -EINVAL; 212 213 if (cops->tcf_chain == NULL) 214 return -EOPNOTSUPP; 215 216 /* Do we search for filter, attached to class? */ 217 if (TC_H_MIN(parent)) { 218 cl = cops->get(q, parent); 219 if (cl == 0) 220 return -ENOENT; 221 } 222 223 /* And the last stroke */ 224 chain = cops->tcf_chain(q, cl); 225 err = -EINVAL; 226 if (chain == NULL) 227 goto errout; 228 if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) { 229 tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER); 230 tcf_destroy_chain(chain); 231 err = 0; 232 goto errout; 233 } 234 235 /* Check the chain for existence of proto-tcf with this priority */ 236 for (back = chain; 237 (tp = rtnl_dereference(*back)) != NULL; 238 back = &tp->next) { 239 if (tp->prio >= prio) { 240 if (tp->prio == prio) { 241 if (!nprio || 242 (tp->protocol != protocol && protocol)) 243 goto errout; 244 } else 245 tp = NULL; 246 break; 247 } 248 } 249 250 if (tp == NULL) { 251 /* Proto-tcf does not exist, create new one */ 252 253 if (tca[TCA_KIND] == NULL || !protocol) 254 goto errout; 255 256 err = -ENOENT; 257 if (n->nlmsg_type != RTM_NEWTFILTER || 258 !(n->nlmsg_flags & NLM_F_CREATE)) 259 goto errout; 260 261 262 /* Create new proto tcf */ 263 264 err = -ENOBUFS; 265 tp = kzalloc(sizeof(*tp), GFP_KERNEL); 266 if (tp == NULL) 267 goto errout; 268 err = -ENOENT; 269 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]); 270 if (tp_ops == NULL) { 271 #ifdef CONFIG_MODULES 272 struct nlattr *kind = tca[TCA_KIND]; 273 char name[IFNAMSIZ]; 274 275 if (kind != NULL && 276 nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) { 277 rtnl_unlock(); 278 request_module("cls_%s", name); 279 rtnl_lock(); 280 tp_ops = tcf_proto_lookup_ops(kind); 281 /* We dropped the RTNL semaphore in order to 282 * perform the module load. So, even if we 283 * succeeded in loading the module we have to 284 * replay the request. We indicate this using 285 * -EAGAIN. 286 */ 287 if (tp_ops != NULL) { 288 module_put(tp_ops->owner); 289 err = -EAGAIN; 290 } 291 } 292 #endif 293 kfree(tp); 294 goto errout; 295 } 296 tp->ops = tp_ops; 297 tp->protocol = protocol; 298 tp->prio = nprio ? : 299 TC_H_MAJ(tcf_auto_prio(rtnl_dereference(*back))); 300 tp->q = q; 301 tp->classify = tp_ops->classify; 302 tp->classid = parent; 303 304 err = tp_ops->init(tp); 305 if (err != 0) { 306 module_put(tp_ops->owner); 307 kfree(tp); 308 goto errout; 309 } 310 311 tp_created = 1; 312 313 } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) 314 goto errout; 315 316 fh = tp->ops->get(tp, t->tcm_handle); 317 318 if (fh == 0) { 319 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) { 320 struct tcf_proto *next = rtnl_dereference(tp->next); 321 322 RCU_INIT_POINTER(*back, next); 323 324 tfilter_notify(net, skb, n, tp, fh, 325 RTM_DELTFILTER, false); 326 tcf_destroy(tp, true); 327 err = 0; 328 goto errout; 329 } 330 331 err = -ENOENT; 332 if (n->nlmsg_type != RTM_NEWTFILTER || 333 !(n->nlmsg_flags & NLM_F_CREATE)) 334 goto errout; 335 } else { 336 switch (n->nlmsg_type) { 337 case RTM_NEWTFILTER: 338 err = -EEXIST; 339 if (n->nlmsg_flags & NLM_F_EXCL) { 340 if (tp_created) 341 tcf_destroy(tp, true); 342 goto errout; 343 } 344 break; 345 case RTM_DELTFILTER: 346 err = tp->ops->delete(tp, fh); 347 if (err == 0) { 348 struct tcf_proto *next = rtnl_dereference(tp->next); 349 350 tfilter_notify(net, skb, n, tp, 351 t->tcm_handle, 352 RTM_DELTFILTER, false); 353 if (tcf_destroy(tp, false)) 354 RCU_INIT_POINTER(*back, next); 355 } 356 goto errout; 357 case RTM_GETTFILTER: 358 err = tfilter_notify(net, skb, n, tp, fh, 359 RTM_NEWTFILTER, true); 360 goto errout; 361 default: 362 err = -EINVAL; 363 goto errout; 364 } 365 } 366 367 err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh, 368 n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE); 369 if (err == 0) { 370 if (tp_created) { 371 RCU_INIT_POINTER(tp->next, rtnl_dereference(*back)); 372 rcu_assign_pointer(*back, tp); 373 } 374 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER, false); 375 } else { 376 if (tp_created) 377 tcf_destroy(tp, true); 378 } 379 380 errout: 381 if (cl) 382 cops->put(q, cl); 383 if (err == -EAGAIN) 384 /* Replay the request. */ 385 goto replay; 386 return err; 387 } 388 389 static int tcf_fill_node(struct net *net, struct sk_buff *skb, 390 struct tcf_proto *tp, unsigned long fh, u32 portid, 391 u32 seq, u16 flags, int event) 392 { 393 struct tcmsg *tcm; 394 struct nlmsghdr *nlh; 395 unsigned char *b = skb_tail_pointer(skb); 396 397 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags); 398 if (!nlh) 399 goto out_nlmsg_trim; 400 tcm = nlmsg_data(nlh); 401 tcm->tcm_family = AF_UNSPEC; 402 tcm->tcm__pad1 = 0; 403 tcm->tcm__pad2 = 0; 404 tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex; 405 tcm->tcm_parent = tp->classid; 406 tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol); 407 if (nla_put_string(skb, TCA_KIND, tp->ops->kind)) 408 goto nla_put_failure; 409 tcm->tcm_handle = fh; 410 if (RTM_DELTFILTER != event) { 411 tcm->tcm_handle = 0; 412 if (tp->ops->dump && tp->ops->dump(net, tp, fh, skb, tcm) < 0) 413 goto nla_put_failure; 414 } 415 nlh->nlmsg_len = skb_tail_pointer(skb) - b; 416 return skb->len; 417 418 out_nlmsg_trim: 419 nla_put_failure: 420 nlmsg_trim(skb, b); 421 return -1; 422 } 423 424 static int tfilter_notify(struct net *net, struct sk_buff *oskb, 425 struct nlmsghdr *n, struct tcf_proto *tp, 426 unsigned long fh, int event, bool unicast) 427 { 428 struct sk_buff *skb; 429 u32 portid = oskb ? NETLINK_CB(oskb).portid : 0; 430 431 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 432 if (!skb) 433 return -ENOBUFS; 434 435 if (tcf_fill_node(net, skb, tp, fh, portid, n->nlmsg_seq, 436 n->nlmsg_flags, event) <= 0) { 437 kfree_skb(skb); 438 return -EINVAL; 439 } 440 441 if (unicast) 442 return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT); 443 444 return rtnetlink_send(skb, net, portid, RTNLGRP_TC, 445 n->nlmsg_flags & NLM_F_ECHO); 446 } 447 448 struct tcf_dump_args { 449 struct tcf_walker w; 450 struct sk_buff *skb; 451 struct netlink_callback *cb; 452 }; 453 454 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, 455 struct tcf_walker *arg) 456 { 457 struct tcf_dump_args *a = (void *)arg; 458 struct net *net = sock_net(a->skb->sk); 459 460 return tcf_fill_node(net, a->skb, tp, n, NETLINK_CB(a->cb->skb).portid, 461 a->cb->nlh->nlmsg_seq, NLM_F_MULTI, 462 RTM_NEWTFILTER); 463 } 464 465 /* called with RTNL */ 466 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) 467 { 468 struct net *net = sock_net(skb->sk); 469 int t; 470 int s_t; 471 struct net_device *dev; 472 struct Qdisc *q; 473 struct tcf_proto *tp, __rcu **chain; 474 struct tcmsg *tcm = nlmsg_data(cb->nlh); 475 unsigned long cl = 0; 476 const struct Qdisc_class_ops *cops; 477 struct tcf_dump_args arg; 478 479 if (nlmsg_len(cb->nlh) < sizeof(*tcm)) 480 return skb->len; 481 dev = __dev_get_by_index(net, tcm->tcm_ifindex); 482 if (!dev) 483 return skb->len; 484 485 if (!tcm->tcm_parent) 486 q = dev->qdisc; 487 else 488 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent)); 489 if (!q) 490 goto out; 491 cops = q->ops->cl_ops; 492 if (!cops) 493 goto errout; 494 if (cops->tcf_chain == NULL) 495 goto errout; 496 if (TC_H_MIN(tcm->tcm_parent)) { 497 cl = cops->get(q, tcm->tcm_parent); 498 if (cl == 0) 499 goto errout; 500 } 501 chain = cops->tcf_chain(q, cl); 502 if (chain == NULL) 503 goto errout; 504 505 s_t = cb->args[0]; 506 507 for (tp = rtnl_dereference(*chain), t = 0; 508 tp; tp = rtnl_dereference(tp->next), t++) { 509 if (t < s_t) 510 continue; 511 if (TC_H_MAJ(tcm->tcm_info) && 512 TC_H_MAJ(tcm->tcm_info) != tp->prio) 513 continue; 514 if (TC_H_MIN(tcm->tcm_info) && 515 TC_H_MIN(tcm->tcm_info) != tp->protocol) 516 continue; 517 if (t > s_t) 518 memset(&cb->args[1], 0, 519 sizeof(cb->args)-sizeof(cb->args[0])); 520 if (cb->args[1] == 0) { 521 if (tcf_fill_node(net, skb, tp, 0, 522 NETLINK_CB(cb->skb).portid, 523 cb->nlh->nlmsg_seq, NLM_F_MULTI, 524 RTM_NEWTFILTER) <= 0) 525 break; 526 527 cb->args[1] = 1; 528 } 529 if (tp->ops->walk == NULL) 530 continue; 531 arg.w.fn = tcf_node_dump; 532 arg.skb = skb; 533 arg.cb = cb; 534 arg.w.stop = 0; 535 arg.w.skip = cb->args[1] - 1; 536 arg.w.count = 0; 537 tp->ops->walk(tp, &arg.w); 538 cb->args[1] = arg.w.count + 1; 539 if (arg.w.stop) 540 break; 541 } 542 543 cb->args[0] = t; 544 545 errout: 546 if (cl) 547 cops->put(q, cl); 548 out: 549 return skb->len; 550 } 551 552 void tcf_exts_destroy(struct tcf_exts *exts) 553 { 554 #ifdef CONFIG_NET_CLS_ACT 555 LIST_HEAD(actions); 556 557 tcf_exts_to_list(exts, &actions); 558 tcf_action_destroy(&actions, TCA_ACT_UNBIND); 559 kfree(exts->actions); 560 exts->nr_actions = 0; 561 #endif 562 } 563 EXPORT_SYMBOL(tcf_exts_destroy); 564 565 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb, 566 struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr) 567 { 568 #ifdef CONFIG_NET_CLS_ACT 569 { 570 struct tc_action *act; 571 572 if (exts->police && tb[exts->police]) { 573 act = tcf_action_init_1(net, tb[exts->police], rate_tlv, 574 "police", ovr, TCA_ACT_BIND); 575 if (IS_ERR(act)) 576 return PTR_ERR(act); 577 578 act->type = exts->type = TCA_OLD_COMPAT; 579 exts->actions[0] = act; 580 exts->nr_actions = 1; 581 } else if (exts->action && tb[exts->action]) { 582 LIST_HEAD(actions); 583 int err, i = 0; 584 585 err = tcf_action_init(net, tb[exts->action], rate_tlv, 586 NULL, ovr, TCA_ACT_BIND, 587 &actions); 588 if (err) 589 return err; 590 list_for_each_entry(act, &actions, list) 591 exts->actions[i++] = act; 592 exts->nr_actions = i; 593 } 594 } 595 #else 596 if ((exts->action && tb[exts->action]) || 597 (exts->police && tb[exts->police])) 598 return -EOPNOTSUPP; 599 #endif 600 601 return 0; 602 } 603 EXPORT_SYMBOL(tcf_exts_validate); 604 605 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst, 606 struct tcf_exts *src) 607 { 608 #ifdef CONFIG_NET_CLS_ACT 609 struct tcf_exts old = *dst; 610 611 tcf_tree_lock(tp); 612 dst->nr_actions = src->nr_actions; 613 dst->actions = src->actions; 614 dst->type = src->type; 615 tcf_tree_unlock(tp); 616 617 tcf_exts_destroy(&old); 618 #endif 619 } 620 EXPORT_SYMBOL(tcf_exts_change); 621 622 #ifdef CONFIG_NET_CLS_ACT 623 static struct tc_action *tcf_exts_first_act(struct tcf_exts *exts) 624 { 625 if (exts->nr_actions == 0) 626 return NULL; 627 else 628 return exts->actions[0]; 629 } 630 #endif 631 632 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts) 633 { 634 #ifdef CONFIG_NET_CLS_ACT 635 struct nlattr *nest; 636 637 if (exts->action && exts->nr_actions) { 638 /* 639 * again for backward compatible mode - we want 640 * to work with both old and new modes of entering 641 * tc data even if iproute2 was newer - jhs 642 */ 643 if (exts->type != TCA_OLD_COMPAT) { 644 LIST_HEAD(actions); 645 646 nest = nla_nest_start(skb, exts->action); 647 if (nest == NULL) 648 goto nla_put_failure; 649 650 tcf_exts_to_list(exts, &actions); 651 if (tcf_action_dump(skb, &actions, 0, 0) < 0) 652 goto nla_put_failure; 653 nla_nest_end(skb, nest); 654 } else if (exts->police) { 655 struct tc_action *act = tcf_exts_first_act(exts); 656 nest = nla_nest_start(skb, exts->police); 657 if (nest == NULL || !act) 658 goto nla_put_failure; 659 if (tcf_action_dump_old(skb, act, 0, 0) < 0) 660 goto nla_put_failure; 661 nla_nest_end(skb, nest); 662 } 663 } 664 return 0; 665 666 nla_put_failure: 667 nla_nest_cancel(skb, nest); 668 return -1; 669 #else 670 return 0; 671 #endif 672 } 673 EXPORT_SYMBOL(tcf_exts_dump); 674 675 676 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts) 677 { 678 #ifdef CONFIG_NET_CLS_ACT 679 struct tc_action *a = tcf_exts_first_act(exts); 680 if (a != NULL && tcf_action_copy_stats(skb, a, 1) < 0) 681 return -1; 682 #endif 683 return 0; 684 } 685 EXPORT_SYMBOL(tcf_exts_dump_stats); 686 687 int tcf_exts_get_dev(struct net_device *dev, struct tcf_exts *exts, 688 struct net_device **hw_dev) 689 { 690 #ifdef CONFIG_NET_CLS_ACT 691 const struct tc_action *a; 692 LIST_HEAD(actions); 693 694 if (tc_no_actions(exts)) 695 return -EINVAL; 696 697 tcf_exts_to_list(exts, &actions); 698 list_for_each_entry(a, &actions, list) { 699 if (a->ops->get_dev) { 700 a->ops->get_dev(a, dev_net(dev), hw_dev); 701 break; 702 } 703 } 704 if (*hw_dev) 705 return 0; 706 #endif 707 return -EOPNOTSUPP; 708 } 709 EXPORT_SYMBOL(tcf_exts_get_dev); 710 711 static int __init tc_filter_init(void) 712 { 713 rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, NULL); 714 rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, NULL); 715 rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter, 716 tc_dump_tfilter, NULL); 717 718 return 0; 719 } 720 721 subsys_initcall(tc_filter_init); 722