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 spinlock_t *root_lock; 121 struct tcmsg *t; 122 u32 protocol; 123 u32 prio; 124 u32 nprio; 125 u32 parent; 126 struct net_device *dev; 127 struct Qdisc *q; 128 struct tcf_proto **back, **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; (tp = *back) != NULL; back = &tp->next) { 201 if (tp->prio >= prio) { 202 if (tp->prio == prio) { 203 if (!nprio || 204 (tp->protocol != protocol && protocol)) 205 goto errout; 206 } else 207 tp = NULL; 208 break; 209 } 210 } 211 212 root_lock = qdisc_root_sleeping_lock(q); 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 ? : TC_H_MAJ(tcf_auto_prio(*back)); 263 tp->q = q; 264 tp->classify = tp_ops->classify; 265 tp->classid = parent; 266 267 err = tp_ops->init(tp); 268 if (err != 0) { 269 module_put(tp_ops->owner); 270 kfree(tp); 271 goto errout; 272 } 273 274 tp_created = 1; 275 276 } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) 277 goto errout; 278 279 fh = tp->ops->get(tp, t->tcm_handle); 280 281 if (fh == 0) { 282 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) { 283 spin_lock_bh(root_lock); 284 *back = tp->next; 285 spin_unlock_bh(root_lock); 286 287 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER); 288 tcf_destroy(tp); 289 err = 0; 290 goto errout; 291 } 292 293 err = -ENOENT; 294 if (n->nlmsg_type != RTM_NEWTFILTER || 295 !(n->nlmsg_flags & NLM_F_CREATE)) 296 goto errout; 297 } else { 298 switch (n->nlmsg_type) { 299 case RTM_NEWTFILTER: 300 err = -EEXIST; 301 if (n->nlmsg_flags & NLM_F_EXCL) { 302 if (tp_created) 303 tcf_destroy(tp); 304 goto errout; 305 } 306 break; 307 case RTM_DELTFILTER: 308 err = tp->ops->delete(tp, fh); 309 if (err == 0) 310 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER); 311 goto errout; 312 case RTM_GETTFILTER: 313 err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER); 314 goto errout; 315 default: 316 err = -EINVAL; 317 goto errout; 318 } 319 } 320 321 err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh, 322 n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE); 323 if (err == 0) { 324 if (tp_created) { 325 spin_lock_bh(root_lock); 326 tp->next = *back; 327 *back = tp; 328 spin_unlock_bh(root_lock); 329 } 330 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER); 331 } else { 332 if (tp_created) 333 tcf_destroy(tp); 334 } 335 336 errout: 337 if (cl) 338 cops->put(q, cl); 339 if (err == -EAGAIN) 340 /* Replay the request. */ 341 goto replay; 342 return err; 343 } 344 345 static int tcf_fill_node(struct net *net, struct sk_buff *skb, struct tcf_proto *tp, 346 unsigned long fh, u32 portid, u32 seq, u16 flags, int event) 347 { 348 struct tcmsg *tcm; 349 struct nlmsghdr *nlh; 350 unsigned char *b = skb_tail_pointer(skb); 351 352 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags); 353 if (!nlh) 354 goto out_nlmsg_trim; 355 tcm = nlmsg_data(nlh); 356 tcm->tcm_family = AF_UNSPEC; 357 tcm->tcm__pad1 = 0; 358 tcm->tcm__pad2 = 0; 359 tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex; 360 tcm->tcm_parent = tp->classid; 361 tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol); 362 if (nla_put_string(skb, TCA_KIND, tp->ops->kind)) 363 goto nla_put_failure; 364 tcm->tcm_handle = fh; 365 if (RTM_DELTFILTER != event) { 366 tcm->tcm_handle = 0; 367 if (tp->ops->dump && tp->ops->dump(net, tp, fh, skb, tcm) < 0) 368 goto nla_put_failure; 369 } 370 nlh->nlmsg_len = skb_tail_pointer(skb) - b; 371 return skb->len; 372 373 out_nlmsg_trim: 374 nla_put_failure: 375 nlmsg_trim(skb, b); 376 return -1; 377 } 378 379 static int tfilter_notify(struct net *net, struct sk_buff *oskb, 380 struct nlmsghdr *n, struct tcf_proto *tp, 381 unsigned long fh, int event) 382 { 383 struct sk_buff *skb; 384 u32 portid = oskb ? NETLINK_CB(oskb).portid : 0; 385 386 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 387 if (!skb) 388 return -ENOBUFS; 389 390 if (tcf_fill_node(net, skb, tp, fh, portid, n->nlmsg_seq, 0, event) <= 0) { 391 kfree_skb(skb); 392 return -EINVAL; 393 } 394 395 return rtnetlink_send(skb, net, portid, RTNLGRP_TC, 396 n->nlmsg_flags & NLM_F_ECHO); 397 } 398 399 struct tcf_dump_args { 400 struct tcf_walker w; 401 struct sk_buff *skb; 402 struct netlink_callback *cb; 403 }; 404 405 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, 406 struct tcf_walker *arg) 407 { 408 struct tcf_dump_args *a = (void *)arg; 409 struct net *net = sock_net(a->skb->sk); 410 411 return tcf_fill_node(net, a->skb, tp, n, NETLINK_CB(a->cb->skb).portid, 412 a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER); 413 } 414 415 /* called with RTNL */ 416 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) 417 { 418 struct net *net = sock_net(skb->sk); 419 int t; 420 int s_t; 421 struct net_device *dev; 422 struct Qdisc *q; 423 struct tcf_proto *tp, **chain; 424 struct tcmsg *tcm = nlmsg_data(cb->nlh); 425 unsigned long cl = 0; 426 const struct Qdisc_class_ops *cops; 427 struct tcf_dump_args arg; 428 429 if (nlmsg_len(cb->nlh) < sizeof(*tcm)) 430 return skb->len; 431 dev = __dev_get_by_index(net, tcm->tcm_ifindex); 432 if (!dev) 433 return skb->len; 434 435 if (!tcm->tcm_parent) 436 q = dev->qdisc; 437 else 438 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent)); 439 if (!q) 440 goto out; 441 cops = q->ops->cl_ops; 442 if (!cops) 443 goto errout; 444 if (cops->tcf_chain == NULL) 445 goto errout; 446 if (TC_H_MIN(tcm->tcm_parent)) { 447 cl = cops->get(q, tcm->tcm_parent); 448 if (cl == 0) 449 goto errout; 450 } 451 chain = cops->tcf_chain(q, cl); 452 if (chain == NULL) 453 goto errout; 454 455 s_t = cb->args[0]; 456 457 for (tp = *chain, t = 0; tp; tp = tp->next, t++) { 458 if (t < s_t) 459 continue; 460 if (TC_H_MAJ(tcm->tcm_info) && 461 TC_H_MAJ(tcm->tcm_info) != tp->prio) 462 continue; 463 if (TC_H_MIN(tcm->tcm_info) && 464 TC_H_MIN(tcm->tcm_info) != tp->protocol) 465 continue; 466 if (t > s_t) 467 memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0])); 468 if (cb->args[1] == 0) { 469 if (tcf_fill_node(net, skb, tp, 0, NETLINK_CB(cb->skb).portid, 470 cb->nlh->nlmsg_seq, NLM_F_MULTI, 471 RTM_NEWTFILTER) <= 0) 472 break; 473 474 cb->args[1] = 1; 475 } 476 if (tp->ops->walk == NULL) 477 continue; 478 arg.w.fn = tcf_node_dump; 479 arg.skb = skb; 480 arg.cb = cb; 481 arg.w.stop = 0; 482 arg.w.skip = cb->args[1] - 1; 483 arg.w.count = 0; 484 tp->ops->walk(tp, &arg.w); 485 cb->args[1] = arg.w.count + 1; 486 if (arg.w.stop) 487 break; 488 } 489 490 cb->args[0] = t; 491 492 errout: 493 if (cl) 494 cops->put(q, cl); 495 out: 496 return skb->len; 497 } 498 499 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts) 500 { 501 #ifdef CONFIG_NET_CLS_ACT 502 tcf_action_destroy(&exts->actions, TCA_ACT_UNBIND); 503 INIT_LIST_HEAD(&exts->actions); 504 #endif 505 } 506 EXPORT_SYMBOL(tcf_exts_destroy); 507 508 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb, 509 struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr) 510 { 511 #ifdef CONFIG_NET_CLS_ACT 512 { 513 struct tc_action *act; 514 515 INIT_LIST_HEAD(&exts->actions); 516 if (exts->police && tb[exts->police]) { 517 act = tcf_action_init_1(net, tb[exts->police], rate_tlv, 518 "police", ovr, 519 TCA_ACT_BIND); 520 if (IS_ERR(act)) 521 return PTR_ERR(act); 522 523 act->type = exts->type = TCA_OLD_COMPAT; 524 list_add(&act->list, &exts->actions); 525 } else if (exts->action && tb[exts->action]) { 526 int err; 527 err = tcf_action_init(net, tb[exts->action], rate_tlv, 528 NULL, ovr, 529 TCA_ACT_BIND, &exts->actions); 530 if (err) 531 return err; 532 } 533 } 534 #else 535 if ((exts->action && tb[exts->action]) || 536 (exts->police && tb[exts->police])) 537 return -EOPNOTSUPP; 538 #endif 539 540 return 0; 541 } 542 EXPORT_SYMBOL(tcf_exts_validate); 543 544 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst, 545 struct tcf_exts *src) 546 { 547 #ifdef CONFIG_NET_CLS_ACT 548 LIST_HEAD(tmp); 549 tcf_tree_lock(tp); 550 list_splice_init(&dst->actions, &tmp); 551 list_splice(&src->actions, &dst->actions); 552 tcf_tree_unlock(tp); 553 tcf_action_destroy(&tmp, TCA_ACT_UNBIND); 554 #endif 555 } 556 EXPORT_SYMBOL(tcf_exts_change); 557 558 #define tcf_exts_first_act(ext) \ 559 list_first_entry(&(exts)->actions, struct tc_action, list) 560 561 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts) 562 { 563 #ifdef CONFIG_NET_CLS_ACT 564 struct nlattr *nest; 565 566 if (exts->action && !list_empty(&exts->actions)) { 567 /* 568 * again for backward compatible mode - we want 569 * to work with both old and new modes of entering 570 * tc data even if iproute2 was newer - jhs 571 */ 572 if (exts->type != TCA_OLD_COMPAT) { 573 nest = nla_nest_start(skb, exts->action); 574 if (nest == NULL) 575 goto nla_put_failure; 576 if (tcf_action_dump(skb, &exts->actions, 0, 0) < 0) 577 goto nla_put_failure; 578 nla_nest_end(skb, nest); 579 } else if (exts->police) { 580 struct tc_action *act = tcf_exts_first_act(exts); 581 nest = nla_nest_start(skb, exts->police); 582 if (nest == NULL || !act) 583 goto nla_put_failure; 584 if (tcf_action_dump_old(skb, act, 0, 0) < 0) 585 goto nla_put_failure; 586 nla_nest_end(skb, nest); 587 } 588 } 589 return 0; 590 591 nla_put_failure: 592 nla_nest_cancel(skb, nest); 593 return -1; 594 #else 595 return 0; 596 #endif 597 } 598 EXPORT_SYMBOL(tcf_exts_dump); 599 600 601 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts) 602 { 603 #ifdef CONFIG_NET_CLS_ACT 604 struct tc_action *a = tcf_exts_first_act(exts); 605 if (tcf_action_copy_stats(skb, a, 1) < 0) 606 return -1; 607 #endif 608 return 0; 609 } 610 EXPORT_SYMBOL(tcf_exts_dump_stats); 611 612 static int __init tc_filter_init(void) 613 { 614 rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, NULL); 615 rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, NULL); 616 rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter, 617 tc_dump_tfilter, NULL); 618 619 return 0; 620 } 621 622 subsys_initcall(tc_filter_init); 623