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 struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
  44 {
  45         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 sk_buff *oskb, struct nlmsghdr *n,
 103                           struct tcf_proto *tp, unsigned long fh, int event);
 104
 105
 106 /* Select new prio value from the range, managed by kernel. */
 107
 108 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 109 {
 110         u32 first = TC_H_MAKE(0xC0000000U, 0U);
 111
 112         if (tp)
 113                 first = tp->prio-1;
 114
 115         return first;
 116 }
 117
 118 /* Add/change/delete/get a filter node */
 119
 120 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 121 {
 122         struct net *net = sock_net(skb->sk);
 123         struct nlattr *tca[TCA_MAX + 1];
 124         spinlock_t *root_lock;
 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 **back, **chain;
 133         struct tcf_proto *tp;
 134         struct tcf_proto_ops *tp_ops;
 135         const struct Qdisc_class_ops *cops;
 136         unsigned long cl;
 137         unsigned long fh;
 138         int err;
 139         int tp_created = 0;
 140
 141         if (!net_eq(net, &init_net))
 142                 return -EINVAL;
 143
 144 replay:
 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 || !(n->nlmsg_flags&NLM_F_CREATE))
 155                         return -ENOENT;
 156                 prio = TC_H_MAKE(0x80000000U, 0U);
 157         }
 158
 159         /* Find head of filter chain. */
 160
 161         /* Find link */
 162         dev = __dev_get_by_index(&init_net, t->tcm_ifindex);
 163         if (dev == NULL)
 164                 return -ENODEV;
 165
 166         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
 167         if (err < 0)
 168                 return err;
 169
 170         /* Find qdisc */
 171         if (!parent) {
 172                 q = dev->qdisc;
 173                 parent = q->handle;
 174         } else {
 175                 q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
 176                 if (q == NULL)
 177                         return -EINVAL;
 178         }
 179
 180         /* Is it classful? */
 181         if ((cops = q->ops->cl_ops) == NULL)
 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 || (tp->protocol != protocol && protocol))
 205                                         goto errout;
 206                         } else
 207                                 tp = NULL;
 208                         break;
 209                 }
 210         }
 211
 212         root_lock = qdisc_root_sleeping_lock(q);
 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 || !(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(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(skb, n, tp, fh, RTM_DELTFILTER);
 310                         goto errout;
 311                 case RTM_GETTFILTER:
 312                         err = tfilter_notify(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(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(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 pid, 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_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
 351         tcm = NLMSG_DATA(nlh);
 352         tcm->tcm_family = AF_UNSPEC;
 353         tcm->tcm__pad1 = 0;
 354         tcm->tcm__pad2 = 0;
 355         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
 356         tcm->tcm_parent = tp->classid;
 357         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 358         NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
 359         tcm->tcm_handle = fh;
 360         if (RTM_DELTFILTER != event) {
 361                 tcm->tcm_handle = 0;
 362                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 363                         goto nla_put_failure;
 364         }
 365         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 366         return skb->len;
 367
 368 nlmsg_failure:
 369 nla_put_failure:
 370         nlmsg_trim(skb, b);
 371         return -1;
 372 }
 373
 374 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 375                           struct tcf_proto *tp, unsigned long fh, int event)
 376 {
 377         struct sk_buff *skb;
 378         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
 379
 380         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 381         if (!skb)
 382                 return -ENOBUFS;
 383
 384         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
 385                 kfree_skb(skb);
 386                 return -EINVAL;
 387         }
 388
 389         return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC,
 390                               n->nlmsg_flags & NLM_F_ECHO);
 391 }
 392
 393 struct tcf_dump_args {
 394         struct tcf_walker w;
 395         struct sk_buff *skb;
 396         struct netlink_callback *cb;
 397 };
 398
 399 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
 400                          struct tcf_walker *arg)
 401 {
 402         struct tcf_dump_args *a = (void *)arg;
 403
 404         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
 405                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 406 }
 407
 408 /* called with RTNL */
 409 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 410 {
 411         struct net *net = sock_net(skb->sk);
 412         int t;
 413         int s_t;
 414         struct net_device *dev;
 415         struct Qdisc *q;
 416         struct tcf_proto *tp, **chain;
 417         struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh);
 418         unsigned long cl = 0;
 419         const struct Qdisc_class_ops *cops;
 420         struct tcf_dump_args arg;
 421
 422         if (!net_eq(net, &init_net))
 423                 return 0;
 424
 425         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 426                 return skb->len;
 427         if ((dev = __dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
 428                 return skb->len;
 429
 430         if (!tcm->tcm_parent)
 431                 q = dev->qdisc;
 432         else
 433                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 434         if (!q)
 435                 goto out;
 436         if ((cops = q->ops->cl_ops) == NULL)
 437                 goto errout;
 438         if (cops->tcf_chain == NULL)
 439                 goto errout;
 440         if (TC_H_MIN(tcm->tcm_parent)) {
 441                 cl = cops->get(q, tcm->tcm_parent);
 442                 if (cl == 0)
 443                         goto errout;
 444         }
 445         chain = cops->tcf_chain(q, cl);
 446         if (chain == NULL)
 447                 goto errout;
 448
 449         s_t = cb->args[0];
 450
 451         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
 452                 if (t < s_t) continue;
 453                 if (TC_H_MAJ(tcm->tcm_info) &&
 454                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 455                         continue;
 456                 if (TC_H_MIN(tcm->tcm_info) &&
 457                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 458                         continue;
 459                 if (t > s_t)
 460                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 461                 if (cb->args[1] == 0) {
 462                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
 463                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
 464                                           RTM_NEWTFILTER) <= 0)
 465                                 break;
 466
 467                         cb->args[1] = 1;
 468                 }
 469                 if (tp->ops->walk == NULL)
 470                         continue;
 471                 arg.w.fn = tcf_node_dump;
 472                 arg.skb = skb;
 473                 arg.cb = cb;
 474                 arg.w.stop = 0;
 475                 arg.w.skip = cb->args[1]-1;
 476                 arg.w.count = 0;
 477                 tp->ops->walk(tp, &arg.w);
 478                 cb->args[1] = arg.w.count+1;
 479                 if (arg.w.stop)
 480                         break;
 481         }
 482
 483         cb->args[0] = t;
 484
 485 errout:
 486         if (cl)
 487                 cops->put(q, cl);
 488 out:
 489         return skb->len;
 490 }
 491
 492 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 493 {
 494 #ifdef CONFIG_NET_CLS_ACT
 495         if (exts->action) {
 496                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 497                 exts->action = NULL;
 498         }
 499 #endif
 500 }
 501 EXPORT_SYMBOL(tcf_exts_destroy);
 502
 503 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
 504                   struct nlattr *rate_tlv, struct tcf_exts *exts,
 505                   const struct tcf_ext_map *map)
 506 {
 507         memset(exts, 0, sizeof(*exts));
 508
 509 #ifdef CONFIG_NET_CLS_ACT
 510         {
 511                 struct tc_action *act;
 512
 513                 if (map->police && tb[map->police]) {
 514                         act = tcf_action_init_1(tb[map->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 = TCA_OLD_COMPAT;
 521                         exts->action = act;
 522                 } else if (map->action && tb[map->action]) {
 523                         act = tcf_action_init(tb[map->action], rate_tlv, NULL,
 524                                               TCA_ACT_NOREPLACE, TCA_ACT_BIND);
 525                         if (IS_ERR(act))
 526                                 return PTR_ERR(act);
 527
 528                         exts->action = act;
 529                 }
 530         }
 531 #else
 532         if ((map->action && tb[map->action]) ||
 533             (map->police && tb[map->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 (src->action) {
 546                 struct tc_action *act;
 547                 tcf_tree_lock(tp);
 548                 act = dst->action;
 549                 dst->action = src->action;
 550                 tcf_tree_unlock(tp);
 551                 if (act)
 552                         tcf_action_destroy(act, TCA_ACT_UNBIND);
 553         }
 554 #endif
 555 }
 556 EXPORT_SYMBOL(tcf_exts_change);
 557
 558 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 559                   const struct tcf_ext_map *map)
 560 {
 561 #ifdef CONFIG_NET_CLS_ACT
 562         if (map->action && exts->action) {
 563                 /*
 564                  * again for backward compatible mode - we want
 565                  * to work with both old and new modes of entering
 566                  * tc data even if iproute2  was newer - jhs
 567                  */
 568                 struct nlattr *nest;
 569
 570                 if (exts->action->type != TCA_OLD_COMPAT) {
 571                         nest = nla_nest_start(skb, map->action);
 572                         if (nest == NULL)
 573                                 goto nla_put_failure;
 574                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 575                                 goto nla_put_failure;
 576                         nla_nest_end(skb, nest);
 577                 } else if (map->police) {
 578                         nest = nla_nest_start(skb, map->police);
 579                         if (nest == NULL)
 580                                 goto nla_put_failure;
 581                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 582                                 goto nla_put_failure;
 583                         nla_nest_end(skb, nest);
 584                 }
 585         }
 586 #endif
 587         return 0;
 588 nla_put_failure: __attribute__ ((unused))
 589         return -1;
 590 }
 591 EXPORT_SYMBOL(tcf_exts_dump);
 592
 593
 594 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 595                         const struct tcf_ext_map *map)
 596 {
 597 #ifdef CONFIG_NET_CLS_ACT
 598         if (exts->action)
 599                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 600                         goto nla_put_failure;
 601 #endif
 602         return 0;
 603 nla_put_failure: __attribute__ ((unused))
 604         return -1;
 605 }
 606 EXPORT_SYMBOL(tcf_exts_dump_stats);
 607
 608 static int __init tc_filter_init(void)
 609 {
 610         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
 611         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
 612         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 613                                                  tc_dump_tfilter);
 614
 615         return 0;
 616 }
 617
 618 subsys_initcall(tc_filter_init);