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