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   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 <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
  35 static struct tcf_proto_ops *tcf_proto_base __read_mostly;
  36
  37 /* Protects list of registered TC modules. It is pure SMP lock. */
  38 static DEFINE_RWLOCK(cls_mod_lock);
  39
  40 /* Find classifier type by string name */
  41
  42 static struct tcf_proto_ops *tcf_proto_lookup_ops(struct nlattr *kind)
  43 {
  44         struct tcf_proto_ops *t = NULL;
  45
  46         if (kind) {
  47                 read_lock(&cls_mod_lock);
  48                 for (t = tcf_proto_base; t; t = t->next) {
  49                         if (nla_strcmp(kind, t->kind) == 0) {
  50                                 if (!try_module_get(t->owner))
  51                                         t = NULL;
  52                                 break;
  53                         }
  54                 }
  55                 read_unlock(&cls_mod_lock);
  56         }
  57         return t;
  58 }
  59
  60 /* Register(unregister) new classifier type */
  61
  62 int register_tcf_proto_ops(struct tcf_proto_ops *ops)
  63 {
  64         struct tcf_proto_ops *t, **tp;
  65         int rc = -EEXIST;
  66
  67         write_lock(&cls_mod_lock);
  68         for (tp = &tcf_proto_base; (t = *tp) != NULL; tp = &t->next)
  69                 if (!strcmp(ops->kind, t->kind))
  70                         goto out;
  71
  72         ops->next = NULL;
  73         *tp = ops;
  74         rc = 0;
  75 out:
  76         write_unlock(&cls_mod_lock);
  77         return rc;
  78 }
  79 EXPORT_SYMBOL(register_tcf_proto_ops);
  80
  81 int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
  82 {
  83         struct tcf_proto_ops *t, **tp;
  84         int rc = -ENOENT;
  85
  86         write_lock(&cls_mod_lock);
  87         for (tp = &tcf_proto_base; (t=*tp) != NULL; tp = &t->next)
  88                 if (t == ops)
  89                         break;
  90
  91         if (!t)
  92                 goto out;
  93         *tp = t->next;
  94         rc = 0;
  95 out:
  96         write_unlock(&cls_mod_lock);
  97         return rc;
  98 }
  99 EXPORT_SYMBOL(unregister_tcf_proto_ops);
 100
 101 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 102                           struct tcf_proto *tp, unsigned long fh, int event);
 103
 104
 105 /* Select new prio value from the range, managed by kernel. */
 106
 107 static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 108 {
 109         u32 first = TC_H_MAKE(0xC0000000U, 0U);
 110
 111         if (tp)
 112                 first = tp->prio-1;
 113
 114         return first;
 115 }
 116
 117 /* Add/change/delete/get a filter node */
 118
 119 static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 120 {
 121         struct net *net = sock_net(skb->sk);
 122         struct nlattr *tca[TCA_MAX + 1];
 123         struct tcmsg *t;
 124         u32 protocol;
 125         u32 prio;
 126         u32 nprio;
 127         u32 parent;
 128         struct net_device *dev;
 129         struct Qdisc  *q;
 130         struct tcf_proto **back, **chain;
 131         struct tcf_proto *tp;
 132         struct tcf_proto_ops *tp_ops;
 133         const struct Qdisc_class_ops *cops;
 134         unsigned long cl;
 135         unsigned long fh;
 136         int err;
 137
 138         if (net != &init_net)
 139                 return -EINVAL;
 140
 141 replay:
 142         t = NLMSG_DATA(n);
 143         protocol = TC_H_MIN(t->tcm_info);
 144         prio = TC_H_MAJ(t->tcm_info);
 145         nprio = prio;
 146         parent = t->tcm_parent;
 147         cl = 0;
 148
 149         if (prio == 0) {
 150                 /* If no priority is given, user wants we allocated it. */
 151                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 152                         return -ENOENT;
 153                 prio = TC_H_MAKE(0x80000000U, 0U);
 154         }
 155
 156         /* Find head of filter chain. */
 157
 158         /* Find link */
 159         dev = __dev_get_by_index(&init_net, t->tcm_ifindex);
 160         if (dev == NULL)
 161                 return -ENODEV;
 162
 163         err = nlmsg_parse(n, sizeof(*t), tca, TCA_MAX, NULL);
 164         if (err < 0)
 165                 return err;
 166
 167         /* Find qdisc */
 168         if (!parent) {
 169                 struct netdev_queue *dev_queue = &dev->tx_queue;
 170                 q = dev_queue->qdisc_sleeping;
 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         /* Do we search for filter, attached to class? */
 183         if (TC_H_MIN(parent)) {
 184                 cl = cops->get(q, parent);
 185                 if (cl == 0)
 186                         return -ENOENT;
 187         }
 188
 189         /* And the last stroke */
 190         chain = cops->tcf_chain(q, cl);
 191         err = -EINVAL;
 192         if (chain == NULL)
 193                 goto errout;
 194
 195         /* Check the chain for existence of proto-tcf with this priority */
 196         for (back = chain; (tp=*back) != NULL; back = &tp->next) {
 197                 if (tp->prio >= prio) {
 198                         if (tp->prio == prio) {
 199                                 if (!nprio || (tp->protocol != protocol && protocol))
 200                                         goto errout;
 201                         } else
 202                                 tp = NULL;
 203                         break;
 204                 }
 205         }
 206
 207         if (tp == NULL) {
 208                 /* Proto-tcf does not exist, create new one */
 209
 210                 if (tca[TCA_KIND] == NULL || !protocol)
 211                         goto errout;
 212
 213                 err = -ENOENT;
 214                 if (n->nlmsg_type != RTM_NEWTFILTER || !(n->nlmsg_flags&NLM_F_CREATE))
 215                         goto errout;
 216
 217
 218                 /* Create new proto tcf */
 219
 220                 err = -ENOBUFS;
 221                 tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 222                 if (tp == NULL)
 223                         goto errout;
 224                 err = -ENOENT;
 225                 tp_ops = tcf_proto_lookup_ops(tca[TCA_KIND]);
 226                 if (tp_ops == NULL) {
 227 #ifdef CONFIG_KMOD
 228                         struct nlattr *kind = tca[TCA_KIND];
 229                         char name[IFNAMSIZ];
 230
 231                         if (kind != NULL &&
 232                             nla_strlcpy(name, kind, IFNAMSIZ) < IFNAMSIZ) {
 233                                 rtnl_unlock();
 234                                 request_module("cls_%s", name);
 235                                 rtnl_lock();
 236                                 tp_ops = tcf_proto_lookup_ops(kind);
 237                                 /* We dropped the RTNL semaphore in order to
 238                                  * perform the module load.  So, even if we
 239                                  * succeeded in loading the module we have to
 240                                  * replay the request.  We indicate this using
 241                                  * -EAGAIN.
 242                                  */
 243                                 if (tp_ops != NULL) {
 244                                         module_put(tp_ops->owner);
 245                                         err = -EAGAIN;
 246                                 }
 247                         }
 248 #endif
 249                         kfree(tp);
 250                         goto errout;
 251                 }
 252                 tp->ops = tp_ops;
 253                 tp->protocol = protocol;
 254                 tp->prio = nprio ? : tcf_auto_prio(*back);
 255                 tp->q = q;
 256                 tp->classify = tp_ops->classify;
 257                 tp->classid = parent;
 258
 259                 err = tp_ops->init(tp);
 260                 if (err != 0) {
 261                         module_put(tp_ops->owner);
 262                         kfree(tp);
 263                         goto errout;
 264                 }
 265
 266                 qdisc_lock_tree(dev);
 267                 tp->next = *back;
 268                 *back = tp;
 269                 qdisc_unlock_tree(dev);
 270
 271         } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind))
 272                 goto errout;
 273
 274         fh = tp->ops->get(tp, t->tcm_handle);
 275
 276         if (fh == 0) {
 277                 if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 278                         qdisc_lock_tree(dev);
 279                         *back = tp->next;
 280                         qdisc_unlock_tree(dev);
 281
 282                         tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 283                         tcf_destroy(tp);
 284                         err = 0;
 285                         goto errout;
 286                 }
 287
 288                 err = -ENOENT;
 289                 if (n->nlmsg_type != RTM_NEWTFILTER ||
 290                     !(n->nlmsg_flags & NLM_F_CREATE))
 291                         goto errout;
 292         } else {
 293                 switch (n->nlmsg_type) {
 294                 case RTM_NEWTFILTER:
 295                         err = -EEXIST;
 296                         if (n->nlmsg_flags & NLM_F_EXCL)
 297                                 goto errout;
 298                         break;
 299                 case RTM_DELTFILTER:
 300                         err = tp->ops->delete(tp, fh);
 301                         if (err == 0)
 302                                 tfilter_notify(skb, n, tp, fh, RTM_DELTFILTER);
 303                         goto errout;
 304                 case RTM_GETTFILTER:
 305                         err = tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 306                         goto errout;
 307                 default:
 308                         err = -EINVAL;
 309                         goto errout;
 310                 }
 311         }
 312
 313         err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh);
 314         if (err == 0)
 315                 tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER);
 316
 317 errout:
 318         if (cl)
 319                 cops->put(q, cl);
 320         if (err == -EAGAIN)
 321                 /* Replay the request. */
 322                 goto replay;
 323         return err;
 324 }
 325
 326 static int tcf_fill_node(struct sk_buff *skb, struct tcf_proto *tp,
 327                          unsigned long fh, u32 pid, u32 seq, u16 flags, int event)
 328 {
 329         struct tcmsg *tcm;
 330         struct nlmsghdr  *nlh;
 331         unsigned char *b = skb_tail_pointer(skb);
 332
 333         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*tcm), flags);
 334         tcm = NLMSG_DATA(nlh);
 335         tcm->tcm_family = AF_UNSPEC;
 336         tcm->tcm__pad1 = 0;
 337         tcm->tcm__pad1 = 0;
 338         tcm->tcm_ifindex = qdisc_dev(tp->q)->ifindex;
 339         tcm->tcm_parent = tp->classid;
 340         tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 341         NLA_PUT_STRING(skb, TCA_KIND, tp->ops->kind);
 342         tcm->tcm_handle = fh;
 343         if (RTM_DELTFILTER != event) {
 344                 tcm->tcm_handle = 0;
 345                 if (tp->ops->dump && tp->ops->dump(tp, fh, skb, tcm) < 0)
 346                         goto nla_put_failure;
 347         }
 348         nlh->nlmsg_len = skb_tail_pointer(skb) - b;
 349         return skb->len;
 350
 351 nlmsg_failure:
 352 nla_put_failure:
 353         nlmsg_trim(skb, b);
 354         return -1;
 355 }
 356
 357 static int tfilter_notify(struct sk_buff *oskb, struct nlmsghdr *n,
 358                           struct tcf_proto *tp, unsigned long fh, int event)
 359 {
 360         struct sk_buff *skb;
 361         u32 pid = oskb ? NETLINK_CB(oskb).pid : 0;
 362
 363         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
 364         if (!skb)
 365                 return -ENOBUFS;
 366
 367         if (tcf_fill_node(skb, tp, fh, pid, n->nlmsg_seq, 0, event) <= 0) {
 368                 kfree_skb(skb);
 369                 return -EINVAL;
 370         }
 371
 372         return rtnetlink_send(skb, &init_net, pid, RTNLGRP_TC,
 373                               n->nlmsg_flags & NLM_F_ECHO);
 374 }
 375
 376 struct tcf_dump_args {
 377         struct tcf_walker w;
 378         struct sk_buff *skb;
 379         struct netlink_callback *cb;
 380 };
 381
 382 static int tcf_node_dump(struct tcf_proto *tp, unsigned long n,
 383                          struct tcf_walker *arg)
 384 {
 385         struct tcf_dump_args *a = (void *)arg;
 386
 387         return tcf_fill_node(a->skb, tp, n, NETLINK_CB(a->cb->skb).pid,
 388                              a->cb->nlh->nlmsg_seq, NLM_F_MULTI, RTM_NEWTFILTER);
 389 }
 390
 391 static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 392 {
 393         struct net *net = sock_net(skb->sk);
 394         struct netdev_queue *dev_queue;
 395         int t;
 396         int s_t;
 397         struct net_device *dev;
 398         struct Qdisc *q;
 399         struct tcf_proto *tp, **chain;
 400         struct tcmsg *tcm = (struct tcmsg *)NLMSG_DATA(cb->nlh);
 401         unsigned long cl = 0;
 402         const struct Qdisc_class_ops *cops;
 403         struct tcf_dump_args arg;
 404
 405         if (net != &init_net)
 406                 return 0;
 407
 408         if (cb->nlh->nlmsg_len < NLMSG_LENGTH(sizeof(*tcm)))
 409                 return skb->len;
 410         if ((dev = dev_get_by_index(&init_net, tcm->tcm_ifindex)) == NULL)
 411                 return skb->len;
 412
 413         dev_queue = &dev->tx_queue;
 414         if (!tcm->tcm_parent)
 415                 q = dev_queue->qdisc_sleeping;
 416         else
 417                 q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
 418         if (!q)
 419                 goto out;
 420         if ((cops = q->ops->cl_ops) == NULL)
 421                 goto errout;
 422         if (TC_H_MIN(tcm->tcm_parent)) {
 423                 cl = cops->get(q, tcm->tcm_parent);
 424                 if (cl == 0)
 425                         goto errout;
 426         }
 427         chain = cops->tcf_chain(q, cl);
 428         if (chain == NULL)
 429                 goto errout;
 430
 431         s_t = cb->args[0];
 432
 433         for (tp=*chain, t=0; tp; tp = tp->next, t++) {
 434                 if (t < s_t) continue;
 435                 if (TC_H_MAJ(tcm->tcm_info) &&
 436                     TC_H_MAJ(tcm->tcm_info) != tp->prio)
 437                         continue;
 438                 if (TC_H_MIN(tcm->tcm_info) &&
 439                     TC_H_MIN(tcm->tcm_info) != tp->protocol)
 440                         continue;
 441                 if (t > s_t)
 442                         memset(&cb->args[1], 0, sizeof(cb->args)-sizeof(cb->args[0]));
 443                 if (cb->args[1] == 0) {
 444                         if (tcf_fill_node(skb, tp, 0, NETLINK_CB(cb->skb).pid,
 445                                           cb->nlh->nlmsg_seq, NLM_F_MULTI,
 446                                           RTM_NEWTFILTER) <= 0)
 447                                 break;
 448
 449                         cb->args[1] = 1;
 450                 }
 451                 if (tp->ops->walk == NULL)
 452                         continue;
 453                 arg.w.fn = tcf_node_dump;
 454                 arg.skb = skb;
 455                 arg.cb = cb;
 456                 arg.w.stop = 0;
 457                 arg.w.skip = cb->args[1]-1;
 458                 arg.w.count = 0;
 459                 tp->ops->walk(tp, &arg.w);
 460                 cb->args[1] = arg.w.count+1;
 461                 if (arg.w.stop)
 462                         break;
 463         }
 464
 465         cb->args[0] = t;
 466
 467 errout:
 468         if (cl)
 469                 cops->put(q, cl);
 470 out:
 471         dev_put(dev);
 472         return skb->len;
 473 }
 474
 475 void tcf_exts_destroy(struct tcf_proto *tp, struct tcf_exts *exts)
 476 {
 477 #ifdef CONFIG_NET_CLS_ACT
 478         if (exts->action) {
 479                 tcf_action_destroy(exts->action, TCA_ACT_UNBIND);
 480                 exts->action = NULL;
 481         }
 482 #endif
 483 }
 484 EXPORT_SYMBOL(tcf_exts_destroy);
 485
 486 int tcf_exts_validate(struct tcf_proto *tp, struct nlattr **tb,
 487                   struct nlattr *rate_tlv, struct tcf_exts *exts,
 488                   const struct tcf_ext_map *map)
 489 {
 490         memset(exts, 0, sizeof(*exts));
 491
 492 #ifdef CONFIG_NET_CLS_ACT
 493         {
 494                 struct tc_action *act;
 495
 496                 if (map->police && tb[map->police]) {
 497                         act = tcf_action_init_1(tb[map->police], rate_tlv,
 498                                                 "police", TCA_ACT_NOREPLACE,
 499                                                 TCA_ACT_BIND);
 500                         if (IS_ERR(act))
 501                                 return PTR_ERR(act);
 502
 503                         act->type = TCA_OLD_COMPAT;
 504                         exts->action = act;
 505                 } else if (map->action && tb[map->action]) {
 506                         act = tcf_action_init(tb[map->action], rate_tlv, NULL,
 507                                               TCA_ACT_NOREPLACE, TCA_ACT_BIND);
 508                         if (IS_ERR(act))
 509                                 return PTR_ERR(act);
 510
 511                         exts->action = act;
 512                 }
 513         }
 514 #else
 515         if ((map->action && tb[map->action]) ||
 516             (map->police && tb[map->police]))
 517                 return -EOPNOTSUPP;
 518 #endif
 519
 520         return 0;
 521 }
 522 EXPORT_SYMBOL(tcf_exts_validate);
 523
 524 void tcf_exts_change(struct tcf_proto *tp, struct tcf_exts *dst,
 525                      struct tcf_exts *src)
 526 {
 527 #ifdef CONFIG_NET_CLS_ACT
 528         if (src->action) {
 529                 struct tc_action *act;
 530                 tcf_tree_lock(tp);
 531                 act = xchg(&dst->action, src->action);
 532                 tcf_tree_unlock(tp);
 533                 if (act)
 534                         tcf_action_destroy(act, TCA_ACT_UNBIND);
 535         }
 536 #endif
 537 }
 538 EXPORT_SYMBOL(tcf_exts_change);
 539
 540 int tcf_exts_dump(struct sk_buff *skb, struct tcf_exts *exts,
 541                   const struct tcf_ext_map *map)
 542 {
 543 #ifdef CONFIG_NET_CLS_ACT
 544         if (map->action && exts->action) {
 545                 /*
 546                  * again for backward compatible mode - we want
 547                  * to work with both old and new modes of entering
 548                  * tc data even if iproute2  was newer - jhs
 549                  */
 550                 struct nlattr *nest;
 551
 552                 if (exts->action->type != TCA_OLD_COMPAT) {
 553                         nest = nla_nest_start(skb, map->action);
 554                         if (nest == NULL)
 555                                 goto nla_put_failure;
 556                         if (tcf_action_dump(skb, exts->action, 0, 0) < 0)
 557                                 goto nla_put_failure;
 558                         nla_nest_end(skb, nest);
 559                 } else if (map->police) {
 560                         nest = nla_nest_start(skb, map->police);
 561                         if (nest == NULL)
 562                                 goto nla_put_failure;
 563                         if (tcf_action_dump_old(skb, exts->action, 0, 0) < 0)
 564                                 goto nla_put_failure;
 565                         nla_nest_end(skb, nest);
 566                 }
 567         }
 568 #endif
 569         return 0;
 570 nla_put_failure: __attribute__ ((unused))
 571         return -1;
 572 }
 573 EXPORT_SYMBOL(tcf_exts_dump);
 574
 575
 576 int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts,
 577                         const struct tcf_ext_map *map)
 578 {
 579 #ifdef CONFIG_NET_CLS_ACT
 580         if (exts->action)
 581                 if (tcf_action_copy_stats(skb, exts->action, 1) < 0)
 582                         goto nla_put_failure;
 583 #endif
 584         return 0;
 585 nla_put_failure: __attribute__ ((unused))
 586         return -1;
 587 }
 588 EXPORT_SYMBOL(tcf_exts_dump_stats);
 589
 590 static int __init tc_filter_init(void)
 591 {
 592         rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL);
 593         rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL);
 594         rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 595                                                  tc_dump_tfilter);
 596
 597         return 0;
 598 }
 599
 600 subsys_initcall(tc_filter_init);