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 static LIST_HEAD(tcf_proto_base);
  35
  36 /* Protects list of registered TC modules. It is pure SMP lock. */
  37 static DEFINE_RWLOCK(cls_mod_lock);
  38
  39 /* Find classifier type by string name */
  40
  41 static const struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
  42 {
  43         const struct tcf_proto_ops *t, *res = NULL;
  44
  45         if (kind) {
  46                 read_lock(&cls_mod_lock);
  47                 list_for_each_entry(t, &tcf_proto_base, head) {
  48                         if (nla_strcmp(kind, t->kind) == 0) {
  49                                 if (try_module_get(t->owner))
  50                                         res = t;
  51                                 break;
  52                         }
  53                 }
  54                 read_unlock(&cls_mod_lock);
  55         }
  56         return res;
  57 }
  58
  59 /* Register(unregister) new classifier type */
  60
  61 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
  62 {
  63         struct tcf_proto_ops *t;
  64         int rc = -EEXIST;
  65
  66         write_lock(&cls_mod_lock);
  67         list_for_each_entry(t, &tcf_proto_base, head)
  68                 if (!strcmp(ops->kind, t->kind))
  69                         goto out;
  70
  71         list_add_tail(&ops->head, &tcf_proto_base);
  72         rc = 0;
  73 out:
  74         write_unlock(&cls_mod_lock);
  75         return rc;
  76 }
  77 EXPORT_SYMBOL(register_tcf_proto_ops);
  78
  79 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  80 {
  81         struct tcf_proto_ops *t;
  82         int rc = -ENOENT;
  83
  84         write_lock(&cls_mod_lock);
  85         list_for_each_entry(t, &tcf_proto_base, head) {
  86                 if (t == ops) {
  87                         list_del(&t->head);
  88                         rc = 0;
  89                         break;
  90                 }
  91         }
  92         write_unlock(&cls_mod_lock);
  93         return rc;
  94 }
  95 EXPORT_SYMBOL(unregister_tcf_proto_ops);
  96
  97 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
  98                           struct nlmsghdr *n, struct tcf_proto *tp,
  99                           unsigned long fh, int event);
 100
 101
 102 /* Select new prio value from the range, managed by kernel. */
 103
 104 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 105 {
 106         u32 first = TC_H_MAKE(0xC0000000U, 0U);
 107
 108         if (tp)
 109                 first = tp->prio - 1;
 110
 111         return first;
 112 }
 113
 114 /* Add/change/delete/get a filter node */
 115
 116 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n)
 117 {
 118         struct net *net = sock_net(skb->sk);
 119         struct nlattr *tca[TCA_MAX + 1];
 120         spinlock_t *root_lock;
 121         struct tcmsg *t;
 122         u32 protocol;
 123         u32 prio;
 124         u32 nprio;
 125         u32 parent;
 126         struct net_device *dev;
 127         struct Qdisc  *q;
 128         struct tcf_proto **back, **chain;
 129         struct tcf_proto *tp;
 130         const struct tcf_proto_ops *tp_ops;
 131         const struct Qdisc_class_ops *cops;
 132         unsigned long cl;
 133         unsigned long fh;
 134         int err;
 135         int tp_created = 0;
 136
 137         if ((n->nlmsg_type != RTM_GETTFILTER) && !capable(CAP_NET_ADMIN))
 138                 return -EPERM;
 139
 140 replay:
 141         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
 142         if (err < 0)
 143                 return err;
 144
 145         t = nlmsg_data(n);
 146         protocol = TC_H_MIN(t->tcm_info);
 147         prio = TC_H_MAJ(t->tcm_info);
 148         nprio = prio;
 149         parent = t->tcm_parent;
 150         cl = 0;
 151
 152         if (prio == 0) {
 153                 /* If no priority is given, user wants we allocated it. */
 154                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 155                     !(n->nlmsg_flags & NLM_F_CREATE))
 156                         return -ENOENT;
 157                 prio = TC_H_MAKE(0x80000000U, 0U);
 158         }
 159
 160         /* Find head of filter chain. */
 161
 162         /* Find link */
 163         dev = __dev_get_by_index(net, t->tcm_ifindex);
 164         if (dev == NULL)
 165                 return -ENODEV;
 166
 167         /* Find qdisc */
 168         if (!parent) {
 169                 q = dev->qdisc;
 170                 parent = q->handle;
 171         } else {
 172                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
 173                 if (q == NULL)
 174                         return -EINVAL;
 175         }
 176
 177         /* Is it classful? */
 178         cops = q->ops->cl_ops;
 179         if (!cops)
 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 ||
 203                                     (tp->protocol != protocol && protocol))
 204                                         goto errout;
 205                         } else
 206                                 tp = NULL;
 207                         break;
 208                 }
 209         }
 210
 211         root_lock = qdisc_root_sleeping_lock(q);
 212
 213         if (tp == NULL) {
 214                 /* Proto-tcf does not exist, create new one */
 215
 216                 if (tca[TCA_KIND] == NULL || !protocol)
 217                         goto errout;
 218
 219                 err = -ENOENT;
 220                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 221                     !(n->nlmsg_flags & NLM_F_CREATE))
 222                         goto errout;
 223
 224
 225                 /* Create new proto tcf */
 226
 227                 err = -ENOBUFS;
 228                 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 229                 if (tp == NULL)
 230                         goto errout;
 231                 err = -ENOENT;
 232                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
 233                 if (tp_ops == NULL) {
 234 #ifdef CONFIG_MODULES
 235                         struct nlattr *kind = tca[TCA_KIND];
 236                         char name[IFNAMSIZ];
 237
 238                         if (kind != NULL &&
 239                             nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 240                                 rtnl_unlock();
 241                                 request_module("cls_%s", name);
 242                                 rtnl_lock();
 243                                 tp_ops = tcf_proto_lookup_ops(kind);
 244                                 /* We dropped the RTNL semaphore in order to
 245                                  * perform the module load.  So, even if we
 246                                  * succeeded in loading the module we have to
 247                                  * replay the request.  We indicate this using
 248                                  * -EAGAIN.
 249                                  */
 250                                 if (tp_ops != NULL) {
 251                                         module_put(tp_ops->owner);
 252                                         err = -EAGAIN;
 253                                 }
 254                         }
 255 #endif
 256                         kfree(tp);
 257                         goto errout;
 258                 }
 259                 tp->ops = tp_ops;
 260                 tp->protocol = protocol;
 261                 tp->prio = nprio ? : TC_H_MAJ(tcf_auto_prio(*back));
 262                 tp->q = q;
 263                 tp->classify = tp_ops->classify;
 264                 tp->classid = parent;
 265
 266                 err = tp_ops->init(tp);
 267                 if (err != 0) {
 268                         module_put(tp_ops->owner);
 269                         kfree(tp);
 270                         goto errout;
 271                 }
 272
 273                 tp_created = 1;
 274
 275         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
 276                 goto errout;
 277
 278         fh = tp->ops->get(tp, t->tcm_handle);
 279
 280         if (fh == 0) {
 281                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 282                         spin_lock_bh(root_lock);
 283                         *back = tp->next;
 284                         spin_unlock_bh(root_lock);
 285
 286                         tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
 287                         tcf_destroy(tp);
 288                         err = 0;
 289                         goto errout;
 290                 }
 291
 292                 err = -ENOENT;
 293                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 294                     !(n->nlmsg_flags & NLM_F_CREATE))
 295                         goto errout;
 296         } else {
 297                 switch (n->nlmsg_type) {
 298                 case RTM_NEWTFILTER:
 299                         err = -EEXIST;
 300                         if (n->nlmsg_flags & NLM_F_EXCL) {
 301                                 if (tp_created)
 302                                         tcf_destroy(tp);
 303                                 goto errout;
 304                         }
 305                         break;
 306                 case RTM_DELTFILTER:
 307                         err = tp->ops->delete(tp, fh);
 308                         if (err == 0)
 309                                 tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
 310                         goto errout;
 311                 case RTM_GETTFILTER:
 312                         err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
 313                         goto errout;
 314                 default:
 315                         err = -EINVAL;
 316                         goto errout;
 317                 }
 318         }
 319
 320         err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh);
 321         if (err == 0) {
 322                 if (tp_created) {
 323                         spin_lock_bh(root_lock);
 324                         tp->next = *back;
 325                         *back = tp;
 326                         spin_unlock_bh(root_lock);
 327                 }
 328                 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
 329         } else {
 330                 if (tp_created)
 331                         tcf_destroy(tp);
 332         }
 333
 334 errout:
 335         if (cl)
 336                 cops->put(q, cl);
 337         if (err == -EAGAIN)
 338                 /* Replay the request. */
 339                 goto replay;
 340         return err;
 341 }
 342
 343 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
 344                          unsigned long fh, u32 portid, u32 seq, u16 flags, int event)
 345 {
 346         struct tcmsg *tcm;
 347         struct nlmsghdr  *nlh;
 348         unsigned char *b = skb_tail_pointer(skb);
 349
 350         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
 351         if (!nlh)
 352                 goto out_nlmsg_trim;
 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         if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
 361                 goto nla_put_failure;
 362         tcm->tcm_handle = fh;
 363         if (RTM_DELTFILTER != event) {
 364                 tcm->tcm_handle = 0;
 365                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 366                         goto nla_put_failure;
 367         }
 368         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 369         return skb->len;
 370
 371 out_nlmsg_trim:
 372 nla_put_failure:
 373         nlmsg_trim(skb, b);
 374         return -1;
 375 }
 376
 377 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 378                           struct nlmsghdr *n, struct tcf_proto *tp,
 379                           unsigned long fh, int event)
 380 {
 381         struct sk_buff *skb;
 382         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
 383
 384         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 385         if (!skb)
 386                 return -ENOBUFS;
 387
 388         if (tcf_fill_node(skb, tp, fh, portid, n->nlmsg_seq, 0, event) <= 0) {
 389                 kfree_skb(skb);
 390                 return -EINVAL;
 391         }
 392
 393         return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
 394                               n->nlmsg_flags & NLM_F_ECHO);
 395 }
 396
 397 struct tcf_dump_args {
 398         struct tcf_walker w;
 399         struct sk_buff *skb;
 400         struct netlink_callback *cb;
 401 };
 402
 403 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
 404                          struct tcf_walker *arg)
 405 {
 406         struct tcf_dump_args *a = (void *)arg;
 407
 408         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).portid,
 409                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 410 }
 411
 412 /* called with RTNL */
 413 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 414 {
 415         struct net *net = sock_net(skb->sk);
 416         int t;
 417         int s_t;
 418         struct net_device *dev;
 419         struct Qdisc *q;
 420         struct tcf_proto *tp, **chain;
 421         struct tcmsg *tcm = nlmsg_data(cb->nlh);
 422         unsigned long cl = 0;
 423         const struct Qdisc_class_ops *cops;
 424         struct tcf_dump_args arg;
 425
 426         if (nlmsg_len(cb->nlh) < sizeof(*tcm))
 427                 return skb->len;
 428         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
 429         if (!dev)
 430                 return skb->len;
 431
 432         if (!tcm->tcm_parent)
 433                 q = dev->qdisc;
 434         else
 435                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 436         if (!q)
 437                 goto out;
 438         cops = q->ops->cl_ops;
 439         if (!cops)
 440                 goto errout;
 441         if (cops->tcf_chain == NULL)
 442                 goto errout;
 443         if (TC_H_MIN(tcm->tcm_parent)) {
 444                 cl = cops->get(q, tcm->tcm_parent);
 445                 if (cl == 0)
 446                         goto errout;
 447         }
 448         chain = cops->tcf_chain(q, cl);
 449         if (chain == NULL)
 450                 goto errout;
 451
 452         s_t = cb->args[0];
 453
 454         for (tp = *chain, t = 0; tp; tp = tp->next, t++) {
 455                 if (t < s_t)
 456                         continue;
 457                 if (TC_H_MAJ(tcm->tcm_info) &&
 458                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 459                         continue;
 460                 if (TC_H_MIN(tcm->tcm_info) &&
 461                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 462                         continue;
 463                 if (t > s_t)
 464                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 465                 if (cb->args[1] == 0) {
 466                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).portid,
 467                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
 468                                           RTM_NEWTFILTER) <= 0)
 469                                 break;
 470
 471                         cb->args[1] = 1;
 472                 }
 473                 if (tp->ops->walk == NULL)
 474                         continue;
 475                 arg.w.fn = tcf_node_dump;
 476                 arg.skb = skb;
 477                 arg.cb = cb;
 478                 arg.w.stop = 0;
 479                 arg.w.skip = cb->args[1] - 1;
 480                 arg.w.count = 0;
 481                 tp->ops->walk(tp, &arg.w);
 482                 cb->args[1] = arg.w.count + 1;
 483                 if (arg.w.stop)
 484                         break;
 485         }
 486
 487         cb->args[0] = t;
 488
 489 errout:
 490         if (cl)
 491                 cops->put(q, cl);
 492 out:
 493         return skb->len;
 494 }
 495
 496 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 497 {
 498 #ifdef CONFIG_NET_CLS_ACT
 499         tcf_action_destroy(&exts->actions, TCA_ACT_UNBIND);
 500         INIT_LIST_HEAD(&exts->actions);
 501 #endif
 502 }
 503 EXPORT_SYMBOL(tcf_exts_destroy);
 504
 505 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 506                   struct nlattr *rate_tlv, struct tcf_exts *exts)
 507 {
 508 #ifdef CONFIG_NET_CLS_ACT
 509         {
 510                 struct tc_action *act;
 511
 512                 INIT_LIST_HEAD(&exts->actions);
 513                 if (exts->police && tb[exts->police]) {
 514                         act = tcf_action_init_1(net, tb[exts->police], rate_tlv,
 515                                                 "police", TCA_ACT_NOREPLACE,
 516                                                 TCA_ACT_BIND);
 517                         if (IS_ERR(act))
 518                                 return PTR_ERR(act);
 519
 520                         act->type = exts->type = TCA_OLD_COMPAT;
 521                         list_add(&act->list, &exts->actions);
 522                 } else if (exts->action && tb[exts->action]) {
 523                         int err;
 524                         err = tcf_action_init(net, tb[exts->action], rate_tlv,
 525                                               NULL, TCA_ACT_NOREPLACE,
 526                                               TCA_ACT_BIND, &exts->actions);
 527                         if (err)
 528                                 return err;
 529                 }
 530         }
 531 #else
 532         if ((exts->action && tb[exts->action]) ||
 533             (exts->police && tb[exts->police]))
 534                 return -EOPNOTSUPP;
 535 #endif
 536
 537         return 0;
 538 }
 539 EXPORT_SYMBOL(tcf_exts_validate);
 540
 541 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 542                      struct tcf_exts *src)
 543 {
 544 #ifdef CONFIG_NET_CLS_ACT
 545         if (!list_empty(&src->actions)) {
 546                 LIST_HEAD(tmp);
 547                 tcf_tree_lock(tp);
 548                 list_splice_init(&dst->actions, &tmp);
 549                 list_splice(&src->actions, &dst->actions);
 550                 tcf_tree_unlock(tp);
 551                 tcf_action_destroy(&tmp, TCA_ACT_UNBIND);
 552         }
 553 #endif
 554 }
 555 EXPORT_SYMBOL(tcf_exts_change);
 556
 557 #define tcf_exts_first_act(ext) \
 558                 list_first_entry(&(exts)->actions, struct tc_action, list)
 559
 560 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
 561 {
 562 #ifdef CONFIG_NET_CLS_ACT
 563         if (exts->action && !list_empty(&exts->actions)) {
 564                 /*
 565                  * again for backward compatible mode - we want
 566                  * to work with both old and new modes of entering
 567                  * tc data even if iproute2  was newer - jhs
 568                  */
 569                 struct nlattr *nest;
 570                 if (exts->type != TCA_OLD_COMPAT) {
 571                         nest = nla_nest_start(skb, exts->action);
 572                         if (nest == NULL)
 573                                 goto nla_put_failure;
 574                         if (tcf_action_dump(skb, &exts->actions, 0, 0) < 0)
 575                                 goto nla_put_failure;
 576                         nla_nest_end(skb, nest);
 577                 } else if (exts->police) {
 578                         struct tc_action *act = tcf_exts_first_act(exts);
 579                         nest = nla_nest_start(skb, exts->police);
 580                         if (nest == NULL)
 581                                 goto nla_put_failure;
 582                         if (tcf_action_dump_old(skb, act, 0, 0) < 0)
 583                                 goto nla_put_failure;
 584                         nla_nest_end(skb, nest);
 585                 }
 586         }
 587 #endif
 588         return 0;
 589 nla_put_failure: __attribute__ ((unused))
 590         return -1;
 591 }
 592 EXPORT_SYMBOL(tcf_exts_dump);
 593
 594
 595 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
 596 {
 597 #ifdef CONFIG_NET_CLS_ACT
 598         struct tc_action *a = tcf_exts_first_act(exts);
 599         if (tcf_action_copy_stats(skb, a, 1) < 0)
 600                 return -1;
 601 #endif
 602         return 0;
 603 }
 604 EXPORT_SYMBOL(tcf_exts_dump_stats);
 605
 606 static int __init tc_filter_init(void)
 607 {
 608         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, NULL);
 609         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, NULL);
 610         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 611                       tc_dump_tfilter, NULL);
 612
 613         return 0;
 614 }
 615
 616 subsys_initcall(tc_filter_init);