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 <linux/slab.h> 28 #include <net/net_namespace.h> 29 #include <net/sock.h> 30 #include <net/netlink.h> 31 #include <net/pkt_sched.h> 32 #include <net/pkt_cls.h> 33 34 /* The list of all installed classifier types */ 35 36 static struct tcf_proto_ops *tcf_proto_base __read_mostly; 37 38 /* Protects list of registered TC modules. It is pure SMP lock. */ 39 static DEFINE_RWLOCK(cls_mod_lock); 40 41 /* Find classifier type by string name */ 42 43 static const struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind) 44 { 45 const struct tcf_proto_ops *t = NULL; 46 47 if (kind) { 48 read_lock(&cls_mod_lock); 49 for (t = tcf_proto_base; t; t = t->next) { 50 if (nla_strcmp(kind, t->kind) == 0) { 51 if (!try_module_get(t->owner)) 52 t = NULL; 53 break; 54 } 55 } 56 read_unlock(&cls_mod_lock); 57 } 58 return t; 59 } 60 61 /* Register(unregister) new classifier type */ 62 63 int register_tcf_proto_ops(struct tcf_proto_ops *ops) 64 { 65 struct tcf_proto_ops *t, **tp; 66 int rc = -EEXIST; 67 68 write_lock(&cls_mod_lock); 69 for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next) 70 if (!strcmp(ops->kind, t->kind)) 71 goto out; 72 73 ops->next = NULL; 74 *tp = ops; 75 rc = 0; 76 out: 77 write_unlock(&cls_mod_lock); 78 return rc; 79 } 80 EXPORT_SYMBOL(register_tcf_proto_ops); 81 82 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops) 83 { 84 struct tcf_proto_ops *t, **tp; 85 int rc = -ENOENT; 86 87 write_lock(&cls_mod_lock); 88 for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next) 89 if (t == ops) 90 break; 91 92 if (!t) 93 goto out; 94 *tp = t->next; 95 rc = 0; 96 out: 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); 105 106 107 /* Select new prio value from the range, managed by kernel. */ 108 109 static inline u32 tcf_auto_prio(struct tcf_proto *tp) 110 { 111 u32 first = TC_H_MAKE(0xC0000000U, 0U); 112 113 if (tp) 114 first = tp->prio - 1; 115 116 return first; 117 } 118 119 /* Add/change/delete/get a filter node */ 120 121 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg) 122 { 123 struct net *net = sock_net(skb->sk); 124 struct nlattr *tca[TCA_MAX + 1]; 125 spinlock_t *root_lock; 126 struct tcmsg *t; 127 u32 protocol; 128 u32 prio; 129 u32 nprio; 130 u32 parent; 131 struct net_device *dev; 132 struct Qdisc *q; 133 struct tcf_proto **back, **chain; 134 struct tcf_proto *tp; 135 const struct tcf_proto_ops *tp_ops; 136 const struct Qdisc_class_ops *cops; 137 unsigned long cl; 138 unsigned long fh; 139 int err; 140 int tp_created = 0; 141 142 replay: 143 t = NLMSG_DATA(n); 144 protocol = TC_H_MIN(t->tcm_info); 145 prio = TC_H_MAJ(t->tcm_info); 146 nprio = prio; 147 parent = t->tcm_parent; 148 cl = 0; 149 150 if (prio == 0) { 151 /* If no priority is given, user wants we allocated it. */ 152 if (n->nlmsg_type != RTM_NEWTFILTER || 153 !(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(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 q = dev->qdisc; 172 parent = q->handle; 173 } else { 174 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent)); 175 if (q == NULL) 176 return -EINVAL; 177 } 178 179 /* Is it classful? */ 180 cops = q->ops->cl_ops; 181 if (!cops) 182 return -EINVAL; 183 184 if (cops->tcf_chain == NULL) 185 return -EOPNOTSUPP; 186 187 /* Do we search for filter, attached to class? */ 188 if (TC_H_MIN(parent)) { 189 cl = cops->get(q, parent); 190 if (cl == 0) 191 return -ENOENT; 192 } 193 194 /* And the last stroke */ 195 chain = cops->tcf_chain(q, cl); 196 err = -EINVAL; 197 if (chain == NULL) 198 goto errout; 199 200 /* Check the chain for existence of proto-tcf with this priority */ 201 for (back = chain; (tp = *back) != NULL; back = &tp->next) { 202 if (tp->prio >= prio) { 203 if (tp->prio == prio) { 204 if (!nprio || 205 (tp->protocol != protocol && protocol)) 206 goto errout; 207 } else 208 tp = NULL; 209 break; 210 } 211 } 212 213 root_lock = qdisc_root_sleeping_lock(q); 214 215 if (tp == NULL) { 216 /* Proto-tcf does not exist, create new one */ 217 218 if (tca[TCA_KIND] == NULL || !protocol) 219 goto errout; 220 221 err = -ENOENT; 222 if (n->nlmsg_type != RTM_NEWTFILTER || 223 !(n->nlmsg_flags & NLM_F_CREATE)) 224 goto errout; 225 226 227 /* Create new proto tcf */ 228 229 err = -ENOBUFS; 230 tp = kzalloc(sizeof(*tp), GFP_KERNEL); 231 if (tp == NULL) 232 goto errout; 233 err = -ENOENT; 234 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]); 235 if (tp_ops == NULL) { 236 #ifdef CONFIG_MODULES 237 struct nlattr *kind = tca[TCA_KIND]; 238 char name[IFNAMSIZ]; 239 240 if (kind != NULL && 241 nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) { 242 rtnl_unlock(); 243 request_module("cls_%s", name); 244 rtnl_lock(); 245 tp_ops = tcf_proto_lookup_ops(kind); 246 /* We dropped the RTNL semaphore in order to 247 * perform the module load. So, even if we 248 * succeeded in loading the module we have to 249 * replay the request. We indicate this using 250 * -EAGAIN. 251 */ 252 if (tp_ops != NULL) { 253 module_put(tp_ops->owner); 254 err = -EAGAIN; 255 } 256 } 257 #endif 258 kfree(tp); 259 goto errout; 260 } 261 tp->ops = tp_ops; 262 tp->protocol = protocol; 263 tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*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 spin_lock_bh(root_lock); 285 *back = tp->next; 286 spin_unlock_bh(root_lock); 287 288 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER); 289 tcf_destroy(tp); 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); 305 goto errout; 306 } 307 break; 308 case RTM_DELTFILTER: 309 err = tp->ops->delete(tp, fh); 310 if (err == 0) 311 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER); 312 goto errout; 313 case RTM_GETTFILTER: 314 err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER); 315 goto errout; 316 default: 317 err = -EINVAL; 318 goto errout; 319 } 320 } 321 322 err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh); 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 sk_buff *skb, struct tcf_proto *tp, 346 unsigned long fh, u32 pid, 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_NEW(skb, pid, seq, event, sizeof(*tcm), flags); 353 tcm = NLMSG_DATA(nlh); 354 tcm->tcm_family = AF_UNSPEC; 355 tcm->tcm__pad1 = 0; 356 tcm->tcm__pad2 = 0; 357 tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex; 358 tcm->tcm_parent = tp->classid; 359 tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol); 360 NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind); 361 tcm->tcm_handle = fh; 362 if (RTM_DELTFILTER != event) { 363 tcm->tcm_handle = 0; 364 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0) 365 goto nla_put_failure; 366 } 367 nlh->nlmsg_len = skb_tail_pointer(skb) - b; 368 return skb->len; 369 370 nlmsg_failure: 371 nla_put_failure: 372 nlmsg_trim(skb, b); 373 return -1; 374 } 375 376 static int tfilter_notify(struct net *net, struct sk_buff *oskb, 377 struct nlmsghdr *n, struct tcf_proto *tp, 378 unsigned long fh, int event) 379 { 380 struct sk_buff *skb; 381 u32 pid = oskb ? NETLINK_CB(oskb).pid : 0; 382 383 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 384 if (!skb) 385 return -ENOBUFS; 386 387 if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) { 388 kfree_skb(skb); 389 return -EINVAL; 390 } 391 392 return rtnetlink_send(skb, net, pid, RTNLGRP_TC, 393 n->nlmsg_flags & NLM_F_ECHO); 394 } 395 396 struct tcf_dump_args { 397 struct tcf_walker w; 398 struct sk_buff *skb; 399 struct netlink_callback *cb; 400 }; 401 402 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, 403 struct tcf_walker *arg) 404 { 405 struct tcf_dump_args *a = (void *)arg; 406 407 return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid, 408 a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER); 409 } 410 411 /* called with RTNL */ 412 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) 413 { 414 struct net *net = sock_net(skb->sk); 415 int t; 416 int s_t; 417 struct net_device *dev; 418 struct Qdisc *q; 419 struct tcf_proto *tp, **chain; 420 struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh); 421 unsigned long cl = 0; 422 const struct Qdisc_class_ops *cops; 423 struct tcf_dump_args arg; 424 425 if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm))) 426 return skb->len; 427 dev = __dev_get_by_index(net, tcm->tcm_ifindex); 428 if (!dev) 429 return skb->len; 430 431 if (!tcm->tcm_parent) 432 q = dev->qdisc; 433 else 434 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent)); 435 if (!q) 436 goto out; 437 cops = q->ops->cl_ops; 438 if (!cops) 439 goto errout; 440 if (cops->tcf_chain == NULL) 441 goto errout; 442 if (TC_H_MIN(tcm->tcm_parent)) { 443 cl = cops->get(q, tcm->tcm_parent); 444 if (cl == 0) 445 goto errout; 446 } 447 chain = cops->tcf_chain(q, cl); 448 if (chain == NULL) 449 goto errout; 450 451 s_t = cb->args[0]; 452 453 for (tp = *chain, t = 0; tp; tp = tp->next, t++) { 454 if (t < s_t) 455 continue; 456 if (TC_H_MAJ(tcm->tcm_info) && 457 TC_H_MAJ(tcm->tcm_info) != tp->prio) 458 continue; 459 if (TC_H_MIN(tcm->tcm_info) && 460 TC_H_MIN(tcm->tcm_info) != tp->protocol) 461 continue; 462 if (t > s_t) 463 memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0])); 464 if (cb->args[1] == 0) { 465 if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid, 466 cb->nlh->nlmsg_seq, NLM_F_MULTI, 467 RTM_NEWTFILTER) <= 0) 468 break; 469 470 cb->args[1] = 1; 471 } 472 if (tp->ops->walk == NULL) 473 continue; 474 arg.w.fn = tcf_node_dump; 475 arg.skb = skb; 476 arg.cb = cb; 477 arg.w.stop = 0; 478 arg.w.skip = cb->args[1] - 1; 479 arg.w.count = 0; 480 tp->ops->walk(tp, &arg.w); 481 cb->args[1] = arg.w.count + 1; 482 if (arg.w.stop) 483 break; 484 } 485 486 cb->args[0] = t; 487 488 errout: 489 if (cl) 490 cops->put(q, cl); 491 out: 492 return skb->len; 493 } 494 495 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts) 496 { 497 #ifdef CONFIG_NET_CLS_ACT 498 if (exts->action) { 499 tcf_action_destroy(exts->action, TCA_ACT_UNBIND); 500 exts->action = NULL; 501 } 502 #endif 503 } 504 EXPORT_SYMBOL(tcf_exts_destroy); 505 506 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb, 507 struct nlattr *rate_tlv, struct tcf_exts *exts, 508 const struct tcf_ext_map *map) 509 { 510 memset(exts, 0, sizeof(*exts)); 511 512 #ifdef CONFIG_NET_CLS_ACT 513 { 514 struct tc_action *act; 515 516 if (map->police && tb[map->police]) { 517 act = tcf_action_init_1(tb[map->police], rate_tlv, 518 "police", TCA_ACT_NOREPLACE, 519 TCA_ACT_BIND); 520 if (IS_ERR(act)) 521 return PTR_ERR(act); 522 523 act->type = TCA_OLD_COMPAT; 524 exts->action = act; 525 } else if (map->action && tb[map->action]) { 526 act = tcf_action_init(tb[map->action], rate_tlv, NULL, 527 TCA_ACT_NOREPLACE, TCA_ACT_BIND); 528 if (IS_ERR(act)) 529 return PTR_ERR(act); 530 531 exts->action = act; 532 } 533 } 534 #else 535 if ((map->action && tb[map->action]) || 536 (map->police && tb[map->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 if (src->action) { 549 struct tc_action *act; 550 tcf_tree_lock(tp); 551 act = dst->action; 552 dst->action = src->action; 553 tcf_tree_unlock(tp); 554 if (act) 555 tcf_action_destroy(act, TCA_ACT_UNBIND); 556 } 557 #endif 558 } 559 EXPORT_SYMBOL(tcf_exts_change); 560 561 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts, 562 const struct tcf_ext_map *map) 563 { 564 #ifdef CONFIG_NET_CLS_ACT 565 if (map->action && exts->action) { 566 /* 567 * again for backward compatible mode - we want 568 * to work with both old and new modes of entering 569 * tc data even if iproute2 was newer - jhs 570 */ 571 struct nlattr *nest; 572 573 if (exts->action->type != TCA_OLD_COMPAT) { 574 nest = nla_nest_start(skb, map->action); 575 if (nest == NULL) 576 goto nla_put_failure; 577 if (tcf_action_dump(skb, exts->action, 0, 0) < 0) 578 goto nla_put_failure; 579 nla_nest_end(skb, nest); 580 } else if (map->police) { 581 nest = nla_nest_start(skb, map->police); 582 if (nest == NULL) 583 goto nla_put_failure; 584 if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0) 585 goto nla_put_failure; 586 nla_nest_end(skb, nest); 587 } 588 } 589 #endif 590 return 0; 591 nla_put_failure: __attribute__ ((unused)) 592 return -1; 593 } 594 EXPORT_SYMBOL(tcf_exts_dump); 595 596 597 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts, 598 const struct tcf_ext_map *map) 599 { 600 #ifdef CONFIG_NET_CLS_ACT 601 if (exts->action) 602 if (tcf_action_copy_stats(skb, exts->action, 1) < 0) 603 goto nla_put_failure; 604 #endif 605 return 0; 606 nla_put_failure: __attribute__ ((unused)) 607 return -1; 608 } 609 EXPORT_SYMBOL(tcf_exts_dump_stats); 610 611 static int __init tc_filter_init(void) 612 { 613 rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, NULL); 614 rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, NULL); 615 rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter, 616 tc_dump_tfilter, NULL); 617 618 return 0; 619 } 620 621 subsys_initcall(tc_filter_init); 622