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 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 const struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind) 43 { 44 const 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 net *net, struct sk_buff *oskb, 102 struct nlmsghdr *n, struct tcf_proto *tp, 103 unsigned long fh, int event); 104 105 106 /* Select new prio value from the range, managed by kernel. */ 107 108 static inline u32 tcf_auto_prio(struct tcf_proto *tp) 109 { 110 u32 first = TC_H_MAKE(0xC0000000U, 0U); 111 112 if (tp) 113 first = tp->prio - 1; 114 115 return first; 116 } 117 118 /* Add/change/delete/get a filter node */ 119 120 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n) 121 { 122 struct net *net = sock_net(skb->sk); 123 struct nlattr *tca[TCA_MAX + 1]; 124 spinlock_t *root_lock; 125 struct tcmsg *t; 126 u32 protocol; 127 u32 prio; 128 u32 nprio; 129 u32 parent; 130 struct net_device *dev; 131 struct Qdisc *q; 132 struct tcf_proto **back, **chain; 133 struct tcf_proto *tp; 134 const struct tcf_proto_ops *tp_ops; 135 const struct Qdisc_class_ops *cops; 136 unsigned long cl; 137 unsigned long fh; 138 int err; 139 int tp_created = 0; 140 141 if ((n->nlmsg_type != RTM_GETTFILTER) && !capable(CAP_NET_ADMIN)) 142 return -EPERM; 143 144 replay: 145 err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL); 146 if (err < 0) 147 return err; 148 149 t = nlmsg_data(n); 150 protocol = TC_H_MIN(t->tcm_info); 151 prio = TC_H_MAJ(t->tcm_info); 152 nprio = prio; 153 parent = t->tcm_parent; 154 cl = 0; 155 156 if (prio == 0) { 157 /* If no priority is given, user wants we allocated it. */ 158 if (n->nlmsg_type != RTM_NEWTFILTER || 159 !(n->nlmsg_flags & NLM_F_CREATE)) 160 return -ENOENT; 161 prio = TC_H_MAKE(0x80000000U, 0U); 162 } 163 164 /* Find head of filter chain. */ 165 166 /* Find link */ 167 dev = __dev_get_by_index(net, t->tcm_ifindex); 168 if (dev == NULL) 169 return -ENODEV; 170 171 /* Find qdisc */ 172 if (!parent) { 173 q = dev->qdisc; 174 parent = q->handle; 175 } else { 176 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent)); 177 if (q == NULL) 178 return -EINVAL; 179 } 180 181 /* Is it classful? */ 182 cops = q->ops->cl_ops; 183 if (!cops) 184 return -EINVAL; 185 186 if (cops->tcf_chain == NULL) 187 return -EOPNOTSUPP; 188 189 /* Do we search for filter, attached to class? */ 190 if (TC_H_MIN(parent)) { 191 cl = cops->get(q, parent); 192 if (cl == 0) 193 return -ENOENT; 194 } 195 196 /* And the last stroke */ 197 chain = cops->tcf_chain(q, cl); 198 err = -EINVAL; 199 if (chain == NULL) 200 goto errout; 201 202 /* Check the chain for existence of proto-tcf with this priority */ 203 for (back = chain; (tp = *back) != NULL; back = &tp->next) { 204 if (tp->prio >= prio) { 205 if (tp->prio == prio) { 206 if (!nprio || 207 (tp->protocol != protocol && protocol)) 208 goto errout; 209 } else 210 tp = NULL; 211 break; 212 } 213 } 214 215 root_lock = qdisc_root_sleeping_lock(q); 216 217 if (tp == NULL) { 218 /* Proto-tcf does not exist, create new one */ 219 220 if (tca[TCA_KIND] == NULL || !protocol) 221 goto errout; 222 223 err = -ENOENT; 224 if (n->nlmsg_type != RTM_NEWTFILTER || 225 !(n->nlmsg_flags & NLM_F_CREATE)) 226 goto errout; 227 228 229 /* Create new proto tcf */ 230 231 err = -ENOBUFS; 232 tp = kzalloc(sizeof(*tp), GFP_KERNEL); 233 if (tp == NULL) 234 goto errout; 235 err = -ENOENT; 236 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]); 237 if (tp_ops == NULL) { 238 #ifdef CONFIG_MODULES 239 struct nlattr *kind = tca[TCA_KIND]; 240 char name[IFNAMSIZ]; 241 242 if (kind != NULL && 243 nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) { 244 rtnl_unlock(); 245 request_module("cls_%s", name); 246 rtnl_lock(); 247 tp_ops = tcf_proto_lookup_ops(kind); 248 /* We dropped the RTNL semaphore in order to 249 * perform the module load. So, even if we 250 * succeeded in loading the module we have to 251 * replay the request. We indicate this using 252 * -EAGAIN. 253 */ 254 if (tp_ops != NULL) { 255 module_put(tp_ops->owner); 256 err = -EAGAIN; 257 } 258 } 259 #endif 260 kfree(tp); 261 goto errout; 262 } 263 tp->ops = tp_ops; 264 tp->protocol = protocol; 265 tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*back)); 266 tp->q = q; 267 tp->classify = tp_ops->classify; 268 tp->classid = parent; 269 270 err = tp_ops->init(tp); 271 if (err != 0) { 272 module_put(tp_ops->owner); 273 kfree(tp); 274 goto errout; 275 } 276 277 tp_created = 1; 278 279 } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) 280 goto errout; 281 282 fh = tp->ops->get(tp, t->tcm_handle); 283 284 if (fh == 0) { 285 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) { 286 spin_lock_bh(root_lock); 287 *back = tp->next; 288 spin_unlock_bh(root_lock); 289 290 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER); 291 tcf_destroy(tp); 292 err = 0; 293 goto errout; 294 } 295 296 err = -ENOENT; 297 if (n->nlmsg_type != RTM_NEWTFILTER || 298 !(n->nlmsg_flags & NLM_F_CREATE)) 299 goto errout; 300 } else { 301 switch (n->nlmsg_type) { 302 case RTM_NEWTFILTER: 303 err = -EEXIST; 304 if (n->nlmsg_flags & NLM_F_EXCL) { 305 if (tp_created) 306 tcf_destroy(tp); 307 goto errout; 308 } 309 break; 310 case RTM_DELTFILTER: 311 err = tp->ops->delete(tp, fh); 312 if (err == 0) 313 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER); 314 goto errout; 315 case RTM_GETTFILTER: 316 err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER); 317 goto errout; 318 default: 319 err = -EINVAL; 320 goto errout; 321 } 322 } 323 324 err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh); 325 if (err == 0) { 326 if (tp_created) { 327 spin_lock_bh(root_lock); 328 tp->next = *back; 329 *back = tp; 330 spin_unlock_bh(root_lock); 331 } 332 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER); 333 } else { 334 if (tp_created) 335 tcf_destroy(tp); 336 } 337 338 errout: 339 if (cl) 340 cops->put(q, cl); 341 if (err == -EAGAIN) 342 /* Replay the request. */ 343 goto replay; 344 return err; 345 } 346 347 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp, 348 unsigned long fh, u32 portid, u32 seq, u16 flags, int event) 349 { 350 struct tcmsg *tcm; 351 struct nlmsghdr *nlh; 352 unsigned char *b = skb_tail_pointer(skb); 353 354 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags); 355 if (!nlh) 356 goto out_nlmsg_trim; 357 tcm = nlmsg_data(nlh); 358 tcm->tcm_family = AF_UNSPEC; 359 tcm->tcm__pad1 = 0; 360 tcm->tcm__pad2 = 0; 361 tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex; 362 tcm->tcm_parent = tp->classid; 363 tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol); 364 if (nla_put_string(skb, TCA_KIND, tp->ops->kind)) 365 goto nla_put_failure; 366 tcm->tcm_handle = fh; 367 if (RTM_DELTFILTER != event) { 368 tcm->tcm_handle = 0; 369 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0) 370 goto nla_put_failure; 371 } 372 nlh->nlmsg_len = skb_tail_pointer(skb) - b; 373 return skb->len; 374 375 out_nlmsg_trim: 376 nla_put_failure: 377 nlmsg_trim(skb, b); 378 return -1; 379 } 380 381 static int tfilter_notify(struct net *net, struct sk_buff *oskb, 382 struct nlmsghdr *n, struct tcf_proto *tp, 383 unsigned long fh, int event) 384 { 385 struct sk_buff *skb; 386 u32 portid = oskb ? NETLINK_CB(oskb).portid : 0; 387 388 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 389 if (!skb) 390 return -ENOBUFS; 391 392 if (tcf_fill_node(skb, tp, fh, portid, n->nlmsg_seq, 0, event) <= 0) { 393 kfree_skb(skb); 394 return -EINVAL; 395 } 396 397 return rtnetlink_send(skb, net, portid, RTNLGRP_TC, 398 n->nlmsg_flags & NLM_F_ECHO); 399 } 400 401 struct tcf_dump_args { 402 struct tcf_walker w; 403 struct sk_buff *skb; 404 struct netlink_callback *cb; 405 }; 406 407 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, 408 struct tcf_walker *arg) 409 { 410 struct tcf_dump_args *a = (void *)arg; 411 412 return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).portid, 413 a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER); 414 } 415 416 /* called with RTNL */ 417 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) 418 { 419 struct net *net = sock_net(skb->sk); 420 int t; 421 int s_t; 422 struct net_device *dev; 423 struct Qdisc *q; 424 struct tcf_proto *tp, **chain; 425 struct tcmsg *tcm = nlmsg_data(cb->nlh); 426 unsigned long cl = 0; 427 const struct Qdisc_class_ops *cops; 428 struct tcf_dump_args arg; 429 430 if (nlmsg_len(cb->nlh) < sizeof(*tcm)) 431 return skb->len; 432 dev = __dev_get_by_index(net, tcm->tcm_ifindex); 433 if (!dev) 434 return skb->len; 435 436 if (!tcm->tcm_parent) 437 q = dev->qdisc; 438 else 439 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent)); 440 if (!q) 441 goto out; 442 cops = q->ops->cl_ops; 443 if (!cops) 444 goto errout; 445 if (cops->tcf_chain == NULL) 446 goto errout; 447 if (TC_H_MIN(tcm->tcm_parent)) { 448 cl = cops->get(q, tcm->tcm_parent); 449 if (cl == 0) 450 goto errout; 451 } 452 chain = cops->tcf_chain(q, cl); 453 if (chain == NULL) 454 goto errout; 455 456 s_t = cb->args[0]; 457 458 for (tp = *chain, t = 0; tp; tp = tp->next, t++) { 459 if (t < s_t) 460 continue; 461 if (TC_H_MAJ(tcm->tcm_info) && 462 TC_H_MAJ(tcm->tcm_info) != tp->prio) 463 continue; 464 if (TC_H_MIN(tcm->tcm_info) && 465 TC_H_MIN(tcm->tcm_info) != tp->protocol) 466 continue; 467 if (t > s_t) 468 memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0])); 469 if (cb->args[1] == 0) { 470 if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).portid, 471 cb->nlh->nlmsg_seq, NLM_F_MULTI, 472 RTM_NEWTFILTER) <= 0) 473 break; 474 475 cb->args[1] = 1; 476 } 477 if (tp->ops->walk == NULL) 478 continue; 479 arg.w.fn = tcf_node_dump; 480 arg.skb = skb; 481 arg.cb = cb; 482 arg.w.stop = 0; 483 arg.w.skip = cb->args[1] - 1; 484 arg.w.count = 0; 485 tp->ops->walk(tp, &arg.w); 486 cb->args[1] = arg.w.count + 1; 487 if (arg.w.stop) 488 break; 489 } 490 491 cb->args[0] = t; 492 493 errout: 494 if (cl) 495 cops->put(q, cl); 496 out: 497 return skb->len; 498 } 499 500 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts) 501 { 502 #ifdef CONFIG_NET_CLS_ACT 503 if (exts->action) { 504 tcf_action_destroy(exts->action, TCA_ACT_UNBIND); 505 exts->action = NULL; 506 } 507 #endif 508 } 509 EXPORT_SYMBOL(tcf_exts_destroy); 510 511 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb, 512 struct nlattr *rate_tlv, struct tcf_exts *exts, 513 const struct tcf_ext_map *map) 514 { 515 memset(exts, 0, sizeof(*exts)); 516 517 #ifdef CONFIG_NET_CLS_ACT 518 { 519 struct tc_action *act; 520 521 if (map->police && tb[map->police]) { 522 act = tcf_action_init_1(net, tb[map->police], rate_tlv, 523 "police", TCA_ACT_NOREPLACE, 524 TCA_ACT_BIND); 525 if (IS_ERR(act)) 526 return PTR_ERR(act); 527 528 act->type = TCA_OLD_COMPAT; 529 exts->action = act; 530 } else if (map->action && tb[map->action]) { 531 act = tcf_action_init(net, tb[map->action], rate_tlv, 532 NULL, TCA_ACT_NOREPLACE, 533 TCA_ACT_BIND); 534 if (IS_ERR(act)) 535 return PTR_ERR(act); 536 537 exts->action = act; 538 } 539 } 540 #else 541 if ((map->action && tb[map->action]) || 542 (map->police && tb[map->police])) 543 return -EOPNOTSUPP; 544 #endif 545 546 return 0; 547 } 548 EXPORT_SYMBOL(tcf_exts_validate); 549 550 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst, 551 struct tcf_exts *src) 552 { 553 #ifdef CONFIG_NET_CLS_ACT 554 if (src->action) { 555 struct tc_action *act; 556 tcf_tree_lock(tp); 557 act = dst->action; 558 dst->action = src->action; 559 tcf_tree_unlock(tp); 560 if (act) 561 tcf_action_destroy(act, TCA_ACT_UNBIND); 562 } 563 #endif 564 } 565 EXPORT_SYMBOL(tcf_exts_change); 566 567 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts, 568 const struct tcf_ext_map *map) 569 { 570 #ifdef CONFIG_NET_CLS_ACT 571 if (map->action && exts->action) { 572 /* 573 * again for backward compatible mode - we want 574 * to work with both old and new modes of entering 575 * tc data even if iproute2 was newer - jhs 576 */ 577 struct nlattr *nest; 578 579 if (exts->action->type != TCA_OLD_COMPAT) { 580 nest = nla_nest_start(skb, map->action); 581 if (nest == NULL) 582 goto nla_put_failure; 583 if (tcf_action_dump(skb, exts->action, 0, 0) < 0) 584 goto nla_put_failure; 585 nla_nest_end(skb, nest); 586 } else if (map->police) { 587 nest = nla_nest_start(skb, map->police); 588 if (nest == NULL) 589 goto nla_put_failure; 590 if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0) 591 goto nla_put_failure; 592 nla_nest_end(skb, nest); 593 } 594 } 595 #endif 596 return 0; 597 nla_put_failure: __attribute__ ((unused)) 598 return -1; 599 } 600 EXPORT_SYMBOL(tcf_exts_dump); 601 602 603 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts, 604 const struct tcf_ext_map *map) 605 { 606 #ifdef CONFIG_NET_CLS_ACT 607 if (exts->action) 608 if (tcf_action_copy_stats(skb, exts->action, 1) < 0) 609 goto nla_put_failure; 610 #endif 611 return 0; 612 nla_put_failure: __attribute__ ((unused)) 613 return -1; 614 } 615 EXPORT_SYMBOL(tcf_exts_dump_stats); 616 617 static int __init tc_filter_init(void) 618 { 619 rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, NULL); 620 rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, NULL); 621 rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter, 622 tc_dump_tfilter, NULL); 623 624 return 0; 625 } 626 627 subsys_initcall(tc_filter_init); 628