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