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