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 36static struct tcf_proto_ops *tcf_proto_base __read_mostly; 37 38/* Protects list of registered TC modules. It is pure SMP lock. */ 39static DEFINE_RWLOCK(cls_mod_lock); 40 41/* Find classifier type by string name */ 42 43static struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind) 44{ 45 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 63int 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; 76out: 77 write_unlock(&cls_mod_lock); 78 return rc; 79} 80EXPORT_SYMBOL(register_tcf_proto_ops); 81 82int 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; 96out: 97 write_unlock(&cls_mod_lock); 98 return rc; 99} 100EXPORT_SYMBOL(unregister_tcf_proto_ops); 101 102static 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 109static 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 121static 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 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 142replay: 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 || !(n->nlmsg_flags&NLM_F_CREATE)) 153 return -ENOENT; 154 prio = TC_H_MAKE(0x80000000U, 0U); 155 } 156 157 /* Find head of filter chain. */ 158 159 /* Find link */ 160 dev = __dev_get_by_index(net, t->tcm_ifindex); 161 if (dev == NULL) 162 return -ENODEV; 163 164 err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL); 165 if (err < 0) 166 return err; 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 if ((cops = q->ops->cl_ops) == NULL) 180 return -EINVAL; 181 182 if (cops->tcf_chain == NULL) 183 return -EOPNOTSUPP; 184 185 /* Do we search for filter, attached to class? */ 186 if (TC_H_MIN(parent)) { 187 cl = cops->get(q, parent); 188 if (cl == 0) 189 return -ENOENT; 190 } 191 192 /* And the last stroke */ 193 chain = cops->tcf_chain(q, cl); 194 err = -EINVAL; 195 if (chain == NULL) 196 goto errout; 197 198 /* Check the chain for existence of proto-tcf with this priority */ 199 for (back = chain; (tp=*back) != NULL; back = &tp->next) { 200 if (tp->prio >= prio) { 201 if (tp->prio == prio) { 202 if (!nprio || (tp->protocol != protocol && protocol)) 203 goto errout; 204 } else 205 tp = NULL; 206 break; 207 } 208 } 209 210 root_lock = qdisc_root_sleeping_lock(q); 211 212 if (tp == NULL) { 213 /* Proto-tcf does not exist, create new one */ 214 215 if (tca[TCA_KIND] == NULL || !protocol) 216 goto errout; 217 218 err = -ENOENT; 219 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE)) 220 goto errout; 221 222 223 /* Create new proto tcf */ 224 225 err = -ENOBUFS; 226 tp = kzalloc(sizeof(*tp), GFP_KERNEL); 227 if (tp == NULL) 228 goto errout; 229 err = -ENOENT; 230 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]); 231 if (tp_ops == NULL) { 232#ifdef CONFIG_MODULES 233 struct nlattr *kind = tca[TCA_KIND]; 234 char name[IFNAMSIZ]; 235 236 if (kind != NULL && 237 nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) { 238 rtnl_unlock(); 239 request_module("cls_%s", name); 240 rtnl_lock(); 241 tp_ops = tcf_proto_lookup_ops(kind); 242 /* We dropped the RTNL semaphore in order to 243 * perform the module load. So, even if we 244 * succeeded in loading the module we have to 245 * replay the request. We indicate this using 246 * -EAGAIN. 247 */ 248 if (tp_ops != NULL) { 249 module_put(tp_ops->owner); 250 err = -EAGAIN; 251 } 252 } 253#endif 254 kfree(tp); 255 goto errout; 256 } 257 tp->ops = tp_ops; 258 tp->protocol = protocol; 259 tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*back)); 260 tp->q = q; 261 tp->classify = tp_ops->classify; 262 tp->classid = parent; 263 264 err = tp_ops->init(tp); 265 if (err != 0) { 266 module_put(tp_ops->owner); 267 kfree(tp); 268 goto errout; 269 } 270 271 tp_created = 1; 272 273 } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) 274 goto errout; 275 276 fh = tp->ops->get(tp, t->tcm_handle); 277 278 if (fh == 0) { 279 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) { 280 spin_lock_bh(root_lock); 281 *back = tp->next; 282 spin_unlock_bh(root_lock); 283 284 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER); 285 tcf_destroy(tp); 286 err = 0; 287 goto errout; 288 } 289 290 err = -ENOENT; 291 if (n->nlmsg_type != RTM_NEWTFILTER || 292 !(n->nlmsg_flags & NLM_F_CREATE)) 293 goto errout; 294 } else { 295 switch (n->nlmsg_type) { 296 case RTM_NEWTFILTER: 297 err = -EEXIST; 298 if (n->nlmsg_flags & NLM_F_EXCL) { 299 if (tp_created) 300 tcf_destroy(tp); 301 goto errout; 302 } 303 break; 304 case RTM_DELTFILTER: 305 err = tp->ops->delete(tp, fh); 306 if (err == 0) 307 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER); 308 goto errout; 309 case RTM_GETTFILTER: 310 err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER); 311 goto errout; 312 default: 313 err = -EINVAL; 314 goto errout; 315 } 316 } 317 318 err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh); 319 if (err == 0) { 320 if (tp_created) { 321 spin_lock_bh(root_lock); 322 tp->next = *back; 323 *back = tp; 324 spin_unlock_bh(root_lock); 325 } 326 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER); 327 } else { 328 if (tp_created) 329 tcf_destroy(tp); 330 } 331 332errout: 333 if (cl) 334 cops->put(q, cl); 335 if (err == -EAGAIN) 336 /* Replay the request. */ 337 goto replay; 338 return err; 339} 340 341static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp, 342 unsigned long fh, u32 pid, u32 seq, u16 flags, int event) 343{ 344 struct tcmsg *tcm; 345 struct nlmsghdr *nlh; 346 unsigned char *b = skb_tail_pointer(skb); 347 348 nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags); 349 tcm = NLMSG_DATA(nlh); 350 tcm->tcm_family = AF_UNSPEC; 351 tcm->tcm__pad1 = 0; 352 tcm->tcm__pad2 = 0; 353 tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex; 354 tcm->tcm_parent = tp->classid; 355 tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol); 356 NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind); 357 tcm->tcm_handle = fh; 358 if (RTM_DELTFILTER != event) { 359 tcm->tcm_handle = 0; 360 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0) 361 goto nla_put_failure; 362 } 363 nlh->nlmsg_len = skb_tail_pointer(skb) - b; 364 return skb->len; 365 366nlmsg_failure: 367nla_put_failure: 368 nlmsg_trim(skb, b); 369 return -1; 370} 371 372static int tfilter_notify(struct net *net, struct sk_buff *oskb, 373 struct nlmsghdr *n, struct tcf_proto *tp, 374 unsigned long fh, int event) 375{ 376 struct sk_buff *skb; 377 u32 pid = oskb ? NETLINK_CB(oskb).pid : 0; 378 379 skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); 380 if (!skb) 381 return -ENOBUFS; 382 383 if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) { 384 kfree_skb(skb); 385 return -EINVAL; 386 } 387 388 return rtnetlink_send(skb, net, pid, RTNLGRP_TC, 389 n->nlmsg_flags & NLM_F_ECHO); 390} 391 392struct tcf_dump_args { 393 struct tcf_walker w; 394 struct sk_buff *skb; 395 struct netlink_callback *cb; 396}; 397 398static int tcf_node_dump(struct tcf_proto *tp, unsigned long n, 399 struct tcf_walker *arg) 400{ 401 struct tcf_dump_args *a = (void *)arg; 402 403 return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid, 404 a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER); 405} 406 407/* called with RTNL */ 408static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) 409{ 410 struct net *net = sock_net(skb->sk); 411 int t; 412 int s_t; 413 struct net_device *dev; 414 struct Qdisc *q; 415 struct tcf_proto *tp, **chain; 416 struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh); 417 unsigned long cl = 0; 418 const struct Qdisc_class_ops *cops; 419 struct tcf_dump_args arg; 420 421 if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm))) 422 return skb->len; 423 if ((dev = __dev_get_by_index(net, tcm->tcm_ifindex)) == NULL) 424 return skb->len; 425 426 if (!tcm->tcm_parent) 427 q = dev->qdisc; 428 else 429 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent)); 430 if (!q) 431 goto out; 432 if ((cops = q->ops->cl_ops) == NULL) 433 goto errout; 434 if (cops->tcf_chain == NULL) 435 goto errout; 436 if (TC_H_MIN(tcm->tcm_parent)) { 437 cl = cops->get(q, tcm->tcm_parent); 438 if (cl == 0) 439 goto errout; 440 } 441 chain = cops->tcf_chain(q, cl); 442 if (chain == NULL) 443 goto errout; 444 445 s_t = cb->args[0]; 446 447 for (tp=*chain, t=0; tp; tp = tp->next, t++) { 448 if (t < s_t) continue; 449 if (TC_H_MAJ(tcm->tcm_info) && 450 TC_H_MAJ(tcm->tcm_info) != tp->prio) 451 continue; 452 if (TC_H_MIN(tcm->tcm_info) && 453 TC_H_MIN(tcm->tcm_info) != tp->protocol) 454 continue; 455 if (t > s_t) 456 memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0])); 457 if (cb->args[1] == 0) { 458 if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid, 459 cb->nlh->nlmsg_seq, NLM_F_MULTI, 460 RTM_NEWTFILTER) <= 0) 461 break; 462 463 cb->args[1] = 1; 464 } 465 if (tp->ops->walk == NULL) 466 continue; 467 arg.w.fn = tcf_node_dump; 468 arg.skb = skb; 469 arg.cb = cb; 470 arg.w.stop = 0; 471 arg.w.skip = cb->args[1]-1; 472 arg.w.count = 0; 473 tp->ops->walk(tp, &arg.w); 474 cb->args[1] = arg.w.count+1; 475 if (arg.w.stop) 476 break; 477 } 478 479 cb->args[0] = t; 480 481errout: 482 if (cl) 483 cops->put(q, cl); 484out: 485 return skb->len; 486} 487 488void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts) 489{ 490#ifdef CONFIG_NET_CLS_ACT 491 if (exts->action) { 492 tcf_action_destroy(exts->action, TCA_ACT_UNBIND); 493 exts->action = NULL; 494 } 495#endif 496} 497EXPORT_SYMBOL(tcf_exts_destroy); 498 499int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb, 500 struct nlattr *rate_tlv, struct tcf_exts *exts, 501 const struct tcf_ext_map *map) 502{ 503 memset(exts, 0, sizeof(*exts)); 504 505#ifdef CONFIG_NET_CLS_ACT 506 { 507 struct tc_action *act; 508 509 if (map->police && tb[map->police]) { 510 act = tcf_action_init_1(tb[map->police], rate_tlv, 511 "police", TCA_ACT_NOREPLACE, 512 TCA_ACT_BIND); 513 if (IS_ERR(act)) 514 return PTR_ERR(act); 515 516 act->type = TCA_OLD_COMPAT; 517 exts->action = act; 518 } else if (map->action && tb[map->action]) { 519 act = tcf_action_init(tb[map->action], rate_tlv, NULL, 520 TCA_ACT_NOREPLACE, TCA_ACT_BIND); 521 if (IS_ERR(act)) 522 return PTR_ERR(act); 523 524 exts->action = act; 525 } 526 } 527#else 528 if ((map->action && tb[map->action]) || 529 (map->police && tb[map->police])) 530 return -EOPNOTSUPP; 531#endif 532 533 return 0; 534} 535EXPORT_SYMBOL(tcf_exts_validate); 536 537void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst, 538 struct tcf_exts *src) 539{ 540#ifdef CONFIG_NET_CLS_ACT 541 if (src->action) { 542 struct tc_action *act; 543 tcf_tree_lock(tp); 544 act = dst->action; 545 dst->action = src->action; 546 tcf_tree_unlock(tp); 547 if (act) 548 tcf_action_destroy(act, TCA_ACT_UNBIND); 549 } 550#endif 551} 552EXPORT_SYMBOL(tcf_exts_change); 553 554int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts, 555 const struct tcf_ext_map *map) 556{ 557#ifdef CONFIG_NET_CLS_ACT 558 if (map->action && exts->action) { 559 /* 560 * again for backward compatible mode - we want 561 * to work with both old and new modes of entering 562 * tc data even if iproute2 was newer - jhs 563 */ 564 struct nlattr *nest; 565 566 if (exts->action->type != TCA_OLD_COMPAT) { 567 nest = nla_nest_start(skb, map->action); 568 if (nest == NULL) 569 goto nla_put_failure; 570 if (tcf_action_dump(skb, exts->action, 0, 0) < 0) 571 goto nla_put_failure; 572 nla_nest_end(skb, nest); 573 } else if (map->police) { 574 nest = nla_nest_start(skb, map->police); 575 if (nest == NULL) 576 goto nla_put_failure; 577 if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0) 578 goto nla_put_failure; 579 nla_nest_end(skb, nest); 580 } 581 } 582#endif 583 return 0; 584nla_put_failure: __attribute__ ((unused)) 585 return -1; 586} 587EXPORT_SYMBOL(tcf_exts_dump); 588 589 590int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts, 591 const struct tcf_ext_map *map) 592{ 593#ifdef CONFIG_NET_CLS_ACT 594 if (exts->action) 595 if (tcf_action_copy_stats(skb, exts->action, 1) < 0) 596 goto nla_put_failure; 597#endif 598 return 0; 599nla_put_failure: __attribute__ ((unused)) 600 return -1; 601} 602EXPORT_SYMBOL(tcf_exts_dump_stats); 603 604static int __init tc_filter_init(void) 605{ 606 rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL); 607 rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL); 608 rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter, 609 tc_dump_tfilter); 610 611 return 0; 612} 613 614subsys_initcall(tc_filter_init); 615