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