net/sched/cls_api.c

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