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