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