kernel/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         /* Wait for outstanding call_rcu()s, if any, from a
  85          * tcf_proto_ops's destroy() handler.
  86          */
  87         rcu_barrier();
  88
  89         write_lock(&cls_mod_lock);
  90         list_for_each_entry(t, &tcf_proto_base, head) {
  91                 if (t == ops) {
  92                         list_del(&t->head);
  93                         rc = 0;
  94                         break;
  95                 }
  96         }
  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         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 __rcu **back;
 133         struct tcf_proto __rcu **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;
 141
 142         if ((n->nlmsg_type != RTM_GETTFILTER) &&
 143             !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
 144                 return -EPERM;
 145
 146 replay:
 147         tp_created = 0;
 148
 149         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
 150         if (err < 0)
 151                 return err;
 152
 153         t = nlmsg_data(n);
 154         protocol = TC_H_MIN(t->tcm_info);
 155         prio = TC_H_MAJ(t->tcm_info);
 156         nprio = prio;
 157         parent = t->tcm_parent;
 158         cl = 0;
 159
 160         if (prio == 0) {
 161                 /* If no priority is given, user wants we allocated it. */
 162                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 163                     !(n->nlmsg_flags & NLM_F_CREATE))
 164                         return -ENOENT;
 165                 prio = TC_H_MAKE(0x80000000U, 0U);
 166         }
 167
 168         /* Find head of filter chain. */
 169
 170         /* Find link */
 171         dev = __dev_get_by_index(net, t->tcm_ifindex);
 172         if (dev == NULL)
 173                 return -ENODEV;
 174
 175         /* Find qdisc */
 176         if (!parent) {
 177                 q = dev->qdisc;
 178                 parent = q->handle;
 179         } else {
 180                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
 181                 if (q == NULL)
 182                         return -EINVAL;
 183         }
 184
 185         /* Is it classful? */
 186         cops = q->ops->cl_ops;
 187         if (!cops)
 188                 return -EINVAL;
 189
 190         if (cops->tcf_chain == NULL)
 191                 return -EOPNOTSUPP;
 192
 193         /* Do we search for filter, attached to class? */
 194         if (TC_H_MIN(parent)) {
 195                 cl = cops->get(q, parent);
 196                 if (cl == 0)
 197                         return -ENOENT;
 198         }
 199
 200         /* And the last stroke */
 201         chain = cops->tcf_chain(q, cl);
 202         err = -EINVAL;
 203         if (chain == NULL)
 204                 goto errout;
 205
 206         /* Check the chain for existence of proto-tcf with this priority */
 207         for (back = chain;
 208              (tp = rtnl_dereference(*back)) != NULL;
 209              back = &tp->next) {
 210                 if (tp->prio >= prio) {
 211                         if (tp->prio == prio) {
 212                                 if (!nprio ||
 213                                     (tp->protocol != protocol && protocol))
 214                                         goto errout;
 215                         } else
 216                                 tp = NULL;
 217                         break;
 218                 }
 219         }
 220
 221         if (tp == NULL) {
 222                 /* Proto-tcf does not exist, create new one */
 223
 224                 if (tca[TCA_KIND] == NULL || !protocol)
 225                         goto errout;
 226
 227                 err = -ENOENT;
 228                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 229                     !(n->nlmsg_flags & NLM_F_CREATE))
 230                         goto errout;
 231
 232
 233                 /* Create new proto tcf */
 234
 235                 err = -ENOBUFS;
 236                 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 237                 if (tp == NULL)
 238                         goto errout;
 239                 err = -ENOENT;
 240                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
 241                 if (tp_ops == NULL) {
 242 #ifdef CONFIG_MODULES
 243                         struct nlattr *kind = tca[TCA_KIND];
 244                         char name[IFNAMSIZ];
 245
 246                         if (kind != NULL &&
 247                             nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 248                                 rtnl_unlock();
 249                                 request_module("cls_%s", name);
 250                                 rtnl_lock();
 251                                 tp_ops = tcf_proto_lookup_ops(kind);
 252                                 /* We dropped the RTNL semaphore in order to
 253                                  * perform the module load.  So, even if we
 254                                  * succeeded in loading the module we have to
 255                                  * replay the request.  We indicate this using
 256                                  * -EAGAIN.
 257                                  */
 258                                 if (tp_ops != NULL) {
 259                                         module_put(tp_ops->owner);
 260                                         err = -EAGAIN;
 261                                 }
 262                         }
 263 #endif
 264                         kfree(tp);
 265                         goto errout;
 266                 }
 267                 tp->ops = tp_ops;
 268                 tp->protocol = protocol;
 269                 tp->prio = nprio ? :
 270                                TC_H_MAJ(tcf_auto_prio(rtnl_dereference(*back)));
 271                 tp->q = q;
 272                 tp->classify = tp_ops->classify;
 273                 tp->classid = parent;
 274
 275                 err = tp_ops->init(tp);
 276                 if (err != 0) {
 277                         module_put(tp_ops->owner);
 278                         kfree(tp);
 279                         goto errout;
 280                 }
 281
 282                 tp_created = 1;
 283
 284         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
 285                 goto errout;
 286
 287         fh = tp->ops->get(tp, t->tcm_handle);
 288
 289         if (fh == 0) {
 290                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 291                         struct tcf_proto *next = rtnl_dereference(tp->next);
 292
 293                         RCU_INIT_POINTER(*back, next);
 294
 295                         tfilter_notify(net, skb, n, tp, fh, RTM_DELTFILTER);
 296                         tcf_destroy(tp, true);
 297                         err = 0;
 298                         goto errout;
 299                 }
 300
 301                 err = -ENOENT;
 302                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 303                     !(n->nlmsg_flags & NLM_F_CREATE))
 304                         goto errout;
 305         } else {
 306                 switch (n->nlmsg_type) {
 307                 case RTM_NEWTFILTER:
 308                         err = -EEXIST;
 309                         if (n->nlmsg_flags & NLM_F_EXCL) {
 310                                 if (tp_created)
 311                                         tcf_destroy(tp, true);
 312                                 goto errout;
 313                         }
 314                         break;
 315                 case RTM_DELTFILTER:
 316                         err = tp->ops->delete(tp, fh);
 317                         if (err == 0) {
 318                                 struct tcf_proto *next = rtnl_dereference(tp->next);
 319
 320                                 tfilter_notify(net, skb, n, tp,
 321                                                t->tcm_handle, RTM_DELTFILTER);
 322                                 if (tcf_destroy(tp, false))
 323                                         RCU_INIT_POINTER(*back, next);
 324                         }
 325                         goto errout;
 326                 case RTM_GETTFILTER:
 327                         err = tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
 328                         goto errout;
 329                 default:
 330                         err = -EINVAL;
 331                         goto errout;
 332                 }
 333         }
 334
 335         err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
 336                               n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE);
 337         if (err == 0) {
 338                 if (tp_created) {
 339                         RCU_INIT_POINTER(tp->next, rtnl_dereference(*back));
 340                         rcu_assign_pointer(*back, tp);
 341                 }
 342                 tfilter_notify(net, skb, n, tp, fh, RTM_NEWTFILTER);
 343         } else {
 344                 if (tp_created)
 345                         tcf_destroy(tp, true);
 346         }
 347
 348 errout:
 349         if (cl)
 350                 cops->put(q, cl);
 351         if (err == -EAGAIN)
 352                 /* Replay the request. */
 353                 goto replay;
 354         return err;
 355 }
 356
 357 static int tcf_fill_node(struct net *net, struct sk_buff *skb, struct tcf_proto *tp,
 358                          unsigned long fh, u32 portid, u32 seq, u16 flags, int event)
 359 {
 360         struct tcmsg *tcm;
 361         struct nlmsghdr  *nlh;
 362         unsigned char *b = skb_tail_pointer(skb);
 363
 364         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*tcm), flags);
 365         if (!nlh)
 366                 goto out_nlmsg_trim;
 367         tcm = nlmsg_data(nlh);
 368         tcm->tcm_family = AF_UNSPEC;
 369         tcm->tcm__pad1 = 0;
 370         tcm->tcm__pad2 = 0;
 371         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
 372         tcm->tcm_parent = tp->classid;
 373         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 374         if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
 375                 goto nla_put_failure;
 376         tcm->tcm_handle = fh;
 377         if (RTM_DELTFILTER != event) {
 378                 tcm->tcm_handle = 0;
 379                 if (tp->ops->dump && tp->ops->dump(net, tp, fh, skb, tcm) < 0)
 380                         goto nla_put_failure;
 381         }
 382         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 383         return skb->len;
 384
 385 out_nlmsg_trim:
 386 nla_put_failure:
 387         nlmsg_trim(skb, b);
 388         return -1;
 389 }
 390
 391 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 392                           struct nlmsghdr *n, struct tcf_proto *tp,
 393                           unsigned long fh, int event)
 394 {
 395         struct sk_buff *skb;
 396         u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
 397
 398         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 399         if (!skb)
 400                 return -ENOBUFS;
 401
 402         if (tcf_fill_node(net, skb, tp, fh, portid, n->nlmsg_seq, 0, event) <= 0) {
 403                 kfree_skb(skb);
 404                 return -EINVAL;
 405         }
 406
 407         return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
 408                               n->nlmsg_flags & NLM_F_ECHO);
 409 }
 410
 411 struct tcf_dump_args {
 412         struct tcf_walker w;
 413         struct sk_buff *skb;
 414         struct netlink_callback *cb;
 415 };
 416
 417 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
 418                          struct tcf_walker *arg)
 419 {
 420         struct tcf_dump_args *a = (void *)arg;
 421         struct net *net = sock_net(a->skb->sk);
 422
 423         return tcf_fill_node(net, a->skb, tp, n, NETLINK_CB(a->cb->skb).portid,
 424                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 425 }
 426
 427 /* called with RTNL */
 428 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 429 {
 430         struct net *net = sock_net(skb->sk);
 431         int t;
 432         int s_t;
 433         struct net_device *dev;
 434         struct Qdisc *q;
 435         struct tcf_proto *tp, __rcu **chain;
 436         struct tcmsg *tcm = nlmsg_data(cb->nlh);
 437         unsigned long cl = 0;
 438         const struct Qdisc_class_ops *cops;
 439         struct tcf_dump_args arg;
 440
 441         if (nlmsg_len(cb->nlh) < sizeof(*tcm))
 442                 return skb->len;
 443         dev = __dev_get_by_index(net, tcm->tcm_ifindex);
 444         if (!dev)
 445                 return skb->len;
 446
 447         if (!tcm->tcm_parent)
 448                 q = dev->qdisc;
 449         else
 450                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 451         if (!q)
 452                 goto out;
 453         cops = q->ops->cl_ops;
 454         if (!cops)
 455                 goto errout;
 456         if (cops->tcf_chain == NULL)
 457                 goto errout;
 458         if (TC_H_MIN(tcm->tcm_parent)) {
 459                 cl = cops->get(q, tcm->tcm_parent);
 460                 if (cl == 0)
 461                         goto errout;
 462         }
 463         chain = cops->tcf_chain(q, cl);
 464         if (chain == NULL)
 465                 goto errout;
 466
 467         s_t = cb->args[0];
 468
 469         for (tp = rtnl_dereference(*chain), t = 0;
 470              tp; tp = rtnl_dereference(tp->next), t++) {
 471                 if (t < s_t)
 472                         continue;
 473                 if (TC_H_MAJ(tcm->tcm_info) &&
 474                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 475                         continue;
 476                 if (TC_H_MIN(tcm->tcm_info) &&
 477                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 478                         continue;
 479                 if (t > s_t)
 480                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 481                 if (cb->args[1] == 0) {
 482                         if (tcf_fill_node(net, skb, tp, 0, NETLINK_CB(cb->skb).portid,
 483                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
 484                                           RTM_NEWTFILTER) <= 0)
 485                                 break;
 486
 487                         cb->args[1] = 1;
 488                 }
 489                 if (tp->ops->walk == NULL)
 490                         continue;
 491                 arg.w.fn = tcf_node_dump;
 492                 arg.skb = skb;
 493                 arg.cb = cb;
 494                 arg.w.stop = 0;
 495                 arg.w.skip = cb->args[1] - 1;
 496                 arg.w.count = 0;
 497                 tp->ops->walk(tp, &arg.w);
 498                 cb->args[1] = arg.w.count + 1;
 499                 if (arg.w.stop)
 500                         break;
 501         }
 502
 503         cb->args[0] = t;
 504
 505 errout:
 506         if (cl)
 507                 cops->put(q, cl);
 508 out:
 509         return skb->len;
 510 }
 511
 512 void tcf_exts_destroy(struct tcf_exts *exts)
 513 {
 514 #ifdef CONFIG_NET_CLS_ACT
 515         tcf_action_destroy(&exts->actions, TCA_ACT_UNBIND);
 516         INIT_LIST_HEAD(&exts->actions);
 517 #endif
 518 }
 519 EXPORT_SYMBOL(tcf_exts_destroy);
 520
 521 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 522                   struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr)
 523 {
 524 #ifdef CONFIG_NET_CLS_ACT
 525         {
 526                 struct tc_action *act;
 527
 528                 INIT_LIST_HEAD(&exts->actions);
 529                 if (exts->police && tb[exts->police]) {
 530                         act = tcf_action_init_1(net, tb[exts->police], rate_tlv,
 531                                                 "police", ovr,
 532                                                 TCA_ACT_BIND);
 533                         if (IS_ERR(act))
 534                                 return PTR_ERR(act);
 535
 536                         act->type = exts->type = TCA_OLD_COMPAT;
 537                         list_add(&act->list, &exts->actions);
 538                 } else if (exts->action && tb[exts->action]) {
 539                         int err;
 540                         err = tcf_action_init(net, tb[exts->action], rate_tlv,
 541                                               NULL, ovr,
 542                                               TCA_ACT_BIND, &exts->actions);
 543                         if (err)
 544                                 return err;
 545                 }
 546         }
 547 #else
 548         if ((exts->action && tb[exts->action]) ||
 549             (exts->police && tb[exts->police]))
 550                 return -EOPNOTSUPP;
 551 #endif
 552
 553         return 0;
 554 }
 555 EXPORT_SYMBOL(tcf_exts_validate);
 556
 557 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 558                      struct tcf_exts *src)
 559 {
 560 #ifdef CONFIG_NET_CLS_ACT
 561         LIST_HEAD(tmp);
 562         tcf_tree_lock(tp);
 563         list_splice_init(&dst->actions, &tmp);
 564         list_splice(&src->actions, &dst->actions);
 565         dst->type = src->type;
 566         tcf_tree_unlock(tp);
 567         tcf_action_destroy(&tmp, TCA_ACT_UNBIND);
 568 #endif
 569 }
 570 EXPORT_SYMBOL(tcf_exts_change);
 571
 572 #define tcf_exts_first_act(ext)                                 \
 573         list_first_entry_or_null(&(exts)->actions,              \
 574                                  struct tc_action, list)
 575
 576 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts)
 577 {
 578 #ifdef CONFIG_NET_CLS_ACT
 579         struct nlattr *nest;
 580
 581         if (exts->action && !list_empty(&exts->actions)) {
 582                 /*
 583                  * again for backward compatible mode - we want
 584                  * to work with both old and new modes of entering
 585                  * tc data even if iproute2  was newer - jhs
 586                  */
 587                 if (exts->type != TCA_OLD_COMPAT) {
 588                         nest = nla_nest_start(skb, exts->action);
 589                         if (nest == NULL)
 590                                 goto nla_put_failure;
 591                         if (tcf_action_dump(skb, &exts->actions, 0, 0) < 0)
 592                                 goto nla_put_failure;
 593                         nla_nest_end(skb, nest);
 594                 } else if (exts->police) {
 595                         struct tc_action *act = tcf_exts_first_act(exts);
 596                         nest = nla_nest_start(skb, exts->police);
 597                         if (nest == NULL || !act)
 598                                 goto nla_put_failure;
 599                         if (tcf_action_dump_old(skb, act, 0, 0) < 0)
 600                                 goto nla_put_failure;
 601                         nla_nest_end(skb, nest);
 602                 }
 603         }
 604         return 0;
 605
 606 nla_put_failure:
 607         nla_nest_cancel(skb, nest);
 608         return -1;
 609 #else
 610         return 0;
 611 #endif
 612 }
 613 EXPORT_SYMBOL(tcf_exts_dump);
 614
 615
 616 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
 617 {
 618 #ifdef CONFIG_NET_CLS_ACT
 619         struct tc_action *a = tcf_exts_first_act(exts);
 620         if (a != NULL && tcf_action_copy_stats(skb, a, 1) < 0)
 621                 return -1;
 622 #endif
 623         return 0;
 624 }
 625 EXPORT_SYMBOL(tcf_exts_dump_stats);
 626
 627 static int __init tc_filter_init(void)
 628 {
 629         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, NULL);
 630         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, NULL);
 631         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 632                       tc_dump_tfilter, NULL);
 633
 634         return 0;
 635 }
 636
 637 subsys_initcall(tc_filter_init);